Chapter 07 Reading Questions Due: 11:59pm on Friday, May 23, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Chapter 7 Reading Quiz Question 17 Part A A lake is currently at high pool, with the same amount of water flowing into the lake as is flowing over the spillway. Which of the following temporary changes would increase the resident time of water in this lake? ANSWER: Chapter 7 Reading Quiz Question 16 Part A A large reservoir behind a dam is rapidly rising, as rain and melting snow add more water than is being released out of the dam’s spillway. In this situation, _____. ANSWER: Chapter 7 Reading Quiz Question 1 Part A Which one of the following statements is correct? ANSWER: Double the rate of water flow into the lake and double the rate of water flow out of the lake, while keeping the lake at the same level. Keep the inflow into the lake the same, but release twice as much water from the lake, resulting in a lowering of the lake level. Decrease the inflow into the lake by half, and decrease the outflow of the lake by half. None of the choices would increase the resident time in the lake. the net flux is positive and the capital of water within the reservoir is decreasing the net flux is positive and the capital of water within the reservoir is increasing the net flux is negative and the capital of water within the reservoir is increasing the net flux is negative and the capital of water within the reservoir is decreasing Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 1 of 8 5/21/2014 8:01 PM Chapter 7 Reading Quiz Question 18 Part A A raging river cascades down a granite mountain and eventually reaches the ocean. At the mouth of the river is a beautiful sandy beach composed of fine grains of granite particles from the river. The entire process of producing this sand is a result of _____. ANSWER: Chapter 7 Reading Quiz Question 4 Part A The physical and chemical properties of soils are primarily determined by _____. ANSWER: Chapter 7 Reading Quiz Question 19 Part A Several inches of rain fall over a field of tall corn, soaking into the soil and draining into ditches. Within an hour, there is no standing water and the humidity over the field rises quickly. At a nearby shopping mall, the rainwater fell onto blacktop and drained to sewer pipes, which carried the water directly into a stream. Which of the following occurred in The cycling time of an element or molecule in an ecosystem is equal to the sum of all the flux times. The cycling time is how long it takes an element or molecule to pass through a biogeochemical cycle. The cycling time of water moving through an ecosystem is typically shorter than the resident time in any pool in this system. The amount of time that water spends in an ocean is the cycling time. mineral evaporation erosion, weathering, transport, and then deposition erosion, dissolution, and precipitation organisms consuming and eroding granite the properties of rock from which the soils develop the amount of precipitation that the soil experiences the range of temperatures that the soil experiences the types of animals that live and move through the soils Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 2 of 8 5/21/2014 8:01 PM the cornfield but not in the parking lot? ANSWER: Chapter 7 Reading Quiz Question 6 Part A Most of the water on Earth is found in _____. ANSWER: Chapter 7 Reading Quiz Question 5 Part A Which one of the following primarily results from the effects of solar energy? ANSWER: Chapter 7 Reading Quiz Question 20 Part A A rural Minnesota farmer grows a variety of vegetables to feed her family. In addition, she cuts down some of her dead trees for firewood to heat her home in the winter. This farmer is adding to the flux of the carbon cycle in her region by _____. precipitation evaporation runoff transpiration the polar ice caps lakes and streams aquifers the oceans evaporation of water from a lake the formation of ice on the top of a pond movement of ocean tides the movement of water over a waterfall Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 3 of 8 5/21/2014 8:01 PM ANSWER: Chapter 7 Reading Quiz Question 8 Part A In a terrestrial ecosystem, most carbon is stored in the biomass of _____. ANSWER: Chapter 7 Reading Quiz Question 7 Part A In which of the following countries would we expect that the terrestrial ecosystems have the highest net primary production and biomass? ANSWER: Chapter 7 Reading Quiz Question 22 Part A Some farmers in the Midwest of the United States rotate their crops from year to year, switching from soybeans to corn on the same fields. What is one of the advantages of doing this? encouraging photosynthesis as she raises crops burning carbon-based fuels by consuming vegetables grown on her farm All of the choices are correct. the animals living there air the top layers of soil containing dead organisms living plants China Australia Brazil United States Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 4 of 8 5/21/2014 8:01 PM ANSWER: Chapter 7 Reading Quiz Question 10 Part A Most nitrogen enters the biosphere through the process of _____ ANSWER: Chapter 7 Reading Quiz Question 9 Part A Where do we expect to find the least amount of nitrogen? ANSWER: Chapter 7 Reading Quiz Question 12 Part A Along the west coast of the United States, upwellings bring deep ocean waters to the surface, carrying with them _____, which greatly increases NPP. ANSWER: The corn crop benefits from reactive nitrogen added to the soil by the soybean crop. Both crops require the same fertilizing supplies, so farmers save by buying fertilizer in bulk. Soybeans add large amounts of carbon dioxide to the soil, which helps the corn crop. Corn adds large amounts of phosphorus to the soil, which helps the soybean crop. nitrogen fixation in which bacteria convert N2 to NH3 cellular respiration, in which animals convert N2 to NH4 fermentation in which bacteria convert N2 to HNO3 photosynthesis, in which plants convert N2 to NO2 in Earth’s crust in plants in animals in the atmosphere Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 5 of 8 5/21/2014 8:01 PM Chapter 7 Reading Quiz Question 11 Part A Which one of the following statements about the carbon, phosphorus, and nitrogen cycles is true? ANSWER: Chapter 7 Reading Quiz Question 24 Part A A large coal-burning power plant is about 50 miles upwind from a lake that used to be popular for fishing. But now, just five years after the plant was constructed, the fish populations are decreasing dramatically. Which one of the following impacts of this coal-burning power plant is most likely hurting the fish populations in this downwind lake? ANSWER: Chapter 7 Reading Quiz Question 14 Part A Which one of the following statements about sulfur is correct? ANSWER: oxygen phosphate carbon sulfur Phosphorus is virtually absent in the atmosphere. The major source of carbon used by plants is the soil. Bacteria drive the phosphorus cycle. The major source of nitrogen used by plants is the air. insufficient sunlight reaching the lake low oxygen levels from burning fossil fuels eutrophication of the lake acidification of the lake Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 6 of 8 5/21/2014 8:01 PM Chapter 7 Reading Quiz Question 13 Part A Nitrogen and sulfur are important to all organisms because they are important constituents of _____. ANSWER: Chapter 7 Reading Quiz Question 25 Part A In Iowa, a small, deep lake in the summer becomes stratified with warmer, less-dense water at the surface and colder, denser water near the bottom. As fall air temperatures decrease, the surface water cools and then drops toward the bottom, mixing the lake levels together. As a result of this mixing, _____. ANSWER: Chapter 7 Reading Quiz Question 15 Part A A fire spreads across hundreds of acres of prairie, burning most of the plant parts above the ground. Compared to before the fire, right after this fire the pool of nutrients in the prairie plants _____. The main pool of sulfur is in the atmosphere where the flux is high and the residence time is long. The main pool of sulfur is in rocks. The flux of sulfur through the atmosphere is high and the residence is short. The main pool of sulfur is in the atmosphere where the flux is low and the residence time is long. The main pool of sulfur is in rocks. The flux of sulfur through the atmosphere is low and the residence is short. nucleic acids glucose phosphates some amino acids nitrogen and phosphorus are added to the lake nitrogen and phosphorus decrease near the surface of the lake nitrogen and phosphorus increase near the surface of the lake None of the choices is correct. Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 7 of 8 5/21/2014 8:01 PM ANSWER: Score Summary: Your score on this assignment is 0.0%. You received 0 out of a possible total of 21 points. and the soil decreases increases and the pool of nutrients in the soil decreases and the soil increases decreases and the pool of nutrients in the soil increases Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 8 of 8 5/21/2014 8:01 PM

Chapter 07 Reading Questions Due: 11:59pm on Friday, May 23, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Chapter 7 Reading Quiz Question 17 Part A A lake is currently at high pool, with the same amount of water flowing into the lake as is flowing over the spillway. Which of the following temporary changes would increase the resident time of water in this lake? ANSWER: Chapter 7 Reading Quiz Question 16 Part A A large reservoir behind a dam is rapidly rising, as rain and melting snow add more water than is being released out of the dam’s spillway. In this situation, _____. ANSWER: Chapter 7 Reading Quiz Question 1 Part A Which one of the following statements is correct? ANSWER: Double the rate of water flow into the lake and double the rate of water flow out of the lake, while keeping the lake at the same level. Keep the inflow into the lake the same, but release twice as much water from the lake, resulting in a lowering of the lake level. Decrease the inflow into the lake by half, and decrease the outflow of the lake by half. None of the choices would increase the resident time in the lake. the net flux is positive and the capital of water within the reservoir is decreasing the net flux is positive and the capital of water within the reservoir is increasing the net flux is negative and the capital of water within the reservoir is increasing the net flux is negative and the capital of water within the reservoir is decreasing Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 1 of 8 5/21/2014 8:01 PM Chapter 7 Reading Quiz Question 18 Part A A raging river cascades down a granite mountain and eventually reaches the ocean. At the mouth of the river is a beautiful sandy beach composed of fine grains of granite particles from the river. The entire process of producing this sand is a result of _____. ANSWER: Chapter 7 Reading Quiz Question 4 Part A The physical and chemical properties of soils are primarily determined by _____. ANSWER: Chapter 7 Reading Quiz Question 19 Part A Several inches of rain fall over a field of tall corn, soaking into the soil and draining into ditches. Within an hour, there is no standing water and the humidity over the field rises quickly. At a nearby shopping mall, the rainwater fell onto blacktop and drained to sewer pipes, which carried the water directly into a stream. Which of the following occurred in The cycling time of an element or molecule in an ecosystem is equal to the sum of all the flux times. The cycling time is how long it takes an element or molecule to pass through a biogeochemical cycle. The cycling time of water moving through an ecosystem is typically shorter than the resident time in any pool in this system. The amount of time that water spends in an ocean is the cycling time. mineral evaporation erosion, weathering, transport, and then deposition erosion, dissolution, and precipitation organisms consuming and eroding granite the properties of rock from which the soils develop the amount of precipitation that the soil experiences the range of temperatures that the soil experiences the types of animals that live and move through the soils Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 2 of 8 5/21/2014 8:01 PM the cornfield but not in the parking lot? ANSWER: Chapter 7 Reading Quiz Question 6 Part A Most of the water on Earth is found in _____. ANSWER: Chapter 7 Reading Quiz Question 5 Part A Which one of the following primarily results from the effects of solar energy? ANSWER: Chapter 7 Reading Quiz Question 20 Part A A rural Minnesota farmer grows a variety of vegetables to feed her family. In addition, she cuts down some of her dead trees for firewood to heat her home in the winter. This farmer is adding to the flux of the carbon cycle in her region by _____. precipitation evaporation runoff transpiration the polar ice caps lakes and streams aquifers the oceans evaporation of water from a lake the formation of ice on the top of a pond movement of ocean tides the movement of water over a waterfall Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 3 of 8 5/21/2014 8:01 PM ANSWER: Chapter 7 Reading Quiz Question 8 Part A In a terrestrial ecosystem, most carbon is stored in the biomass of _____. ANSWER: Chapter 7 Reading Quiz Question 7 Part A In which of the following countries would we expect that the terrestrial ecosystems have the highest net primary production and biomass? ANSWER: Chapter 7 Reading Quiz Question 22 Part A Some farmers in the Midwest of the United States rotate their crops from year to year, switching from soybeans to corn on the same fields. What is one of the advantages of doing this? encouraging photosynthesis as she raises crops burning carbon-based fuels by consuming vegetables grown on her farm All of the choices are correct. the animals living there air the top layers of soil containing dead organisms living plants China Australia Brazil United States Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 4 of 8 5/21/2014 8:01 PM ANSWER: Chapter 7 Reading Quiz Question 10 Part A Most nitrogen enters the biosphere through the process of _____ ANSWER: Chapter 7 Reading Quiz Question 9 Part A Where do we expect to find the least amount of nitrogen? ANSWER: Chapter 7 Reading Quiz Question 12 Part A Along the west coast of the United States, upwellings bring deep ocean waters to the surface, carrying with them _____, which greatly increases NPP. ANSWER: The corn crop benefits from reactive nitrogen added to the soil by the soybean crop. Both crops require the same fertilizing supplies, so farmers save by buying fertilizer in bulk. Soybeans add large amounts of carbon dioxide to the soil, which helps the corn crop. Corn adds large amounts of phosphorus to the soil, which helps the soybean crop. nitrogen fixation in which bacteria convert N2 to NH3 cellular respiration, in which animals convert N2 to NH4 fermentation in which bacteria convert N2 to HNO3 photosynthesis, in which plants convert N2 to NO2 in Earth’s crust in plants in animals in the atmosphere Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 5 of 8 5/21/2014 8:01 PM Chapter 7 Reading Quiz Question 11 Part A Which one of the following statements about the carbon, phosphorus, and nitrogen cycles is true? ANSWER: Chapter 7 Reading Quiz Question 24 Part A A large coal-burning power plant is about 50 miles upwind from a lake that used to be popular for fishing. But now, just five years after the plant was constructed, the fish populations are decreasing dramatically. Which one of the following impacts of this coal-burning power plant is most likely hurting the fish populations in this downwind lake? ANSWER: Chapter 7 Reading Quiz Question 14 Part A Which one of the following statements about sulfur is correct? ANSWER: oxygen phosphate carbon sulfur Phosphorus is virtually absent in the atmosphere. The major source of carbon used by plants is the soil. Bacteria drive the phosphorus cycle. The major source of nitrogen used by plants is the air. insufficient sunlight reaching the lake low oxygen levels from burning fossil fuels eutrophication of the lake acidification of the lake Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 6 of 8 5/21/2014 8:01 PM Chapter 7 Reading Quiz Question 13 Part A Nitrogen and sulfur are important to all organisms because they are important constituents of _____. ANSWER: Chapter 7 Reading Quiz Question 25 Part A In Iowa, a small, deep lake in the summer becomes stratified with warmer, less-dense water at the surface and colder, denser water near the bottom. As fall air temperatures decrease, the surface water cools and then drops toward the bottom, mixing the lake levels together. As a result of this mixing, _____. ANSWER: Chapter 7 Reading Quiz Question 15 Part A A fire spreads across hundreds of acres of prairie, burning most of the plant parts above the ground. Compared to before the fire, right after this fire the pool of nutrients in the prairie plants _____. The main pool of sulfur is in the atmosphere where the flux is high and the residence time is long. The main pool of sulfur is in rocks. The flux of sulfur through the atmosphere is high and the residence is short. The main pool of sulfur is in the atmosphere where the flux is low and the residence time is long. The main pool of sulfur is in rocks. The flux of sulfur through the atmosphere is low and the residence is short. nucleic acids glucose phosphates some amino acids nitrogen and phosphorus are added to the lake nitrogen and phosphorus decrease near the surface of the lake nitrogen and phosphorus increase near the surface of the lake None of the choices is correct. Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 7 of 8 5/21/2014 8:01 PM ANSWER: Score Summary: Your score on this assignment is 0.0%. You received 0 out of a possible total of 21 points. and the soil decreases increases and the pool of nutrients in the soil decreases and the soil increases decreases and the pool of nutrients in the soil increases Chapter 07 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 8 of 8 5/21/2014 8:01 PM

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Chapter 04 Homework Due: 11:59pm on Friday, May 23, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Activity: Investigating Survivorship Curves Click here to complete this activity. Then answer the questions. Part A Which of these species typically has a mortality rate that remains fairly constant over an individual’s life span? ANSWER: Correct The mortality rate of robins remains relatively constant throughout their life span. Part B Oyster populations are primarily, if not exclusively, composed of _____. ANSWER: Correct Young oysters have a very high mortality rate; older oysters have a much lower mortality rate. Thus, most oyster populations consist primarily of older individuals. Part C Which of these organisms has a survivorship curve similar to that of oysters? ANSWER: grasses oysters elephants robins humans juveniles adults prereproductive oysters larval and juvenile oysters larvae Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 1 of 13 5/21/2014 7:59 PM Correct Grasses, like oysters, have a relatively high mortality rate early in their life span, after which the mortality rate decreases. Part D Which of these organisms has a survivorship curve similar to that of humans? ANSWER: Correct The mortality rate of elephants, like that of humans, remains relatively low for much of their life span and then dramatically increases for older individuals. BioFlix Quiz: Population Ecology Watch the animation at left before answering the questions below. cats robins elephants grasses humans cats oysters grasses robins elephants Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 2 of 13 5/21/2014 7:59 PM Part A An ideal habitat with unlimited resources is associated with Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Correct Populations grow exponentially with unlimited resources. Part B The maximum population a habitat can support is its Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Correct Part C Logistic growth involves Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Both exponential growth and logistic growth. Population crashes. Exponential growth. Logistic growth. Neither exponential growth nor logistic growth. Logistic growth. Death rate. Birth rate. Carrying capacity. Exponential growth. A population crash. Population growth continuing forever. Population growth reaching carrying capacity and then speeding up. Population size decreasing to zero. Population growth slowing down as the population approaches carrying capacity. Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 3 of 13 5/21/2014 7:59 PM Correct Part D In exponential growth Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Correct Part E Which of the following would NOT cause population size to decrease? Hint 1. Review the animation. ANSWER: Correct An increased birth rate would cause population size to increase. BioFlix Activity: Photosynthesis — Inputs and Outputs Can you fill in the photosynthesis equation? To review photosynthesis, watch this BioFlix animation: Photosynthesis. Part A – Photosynthesis equation Drag the labels onto the equation to identify the inputs and outputs of photosynthesis. ANSWER: Population size grows more and more slowly as the population gets bigger. Population size grows faster and faster as the population gets bigger. Population size stays constant. Population growth slows as the population gets close to its carrying capacity. None of these are correct. Increased death rate A exponentially growing population outgrowing its food supply and crashing Poor weather, resulting in less food being available Increase in the number of predators Increased birth rate Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 4 of 13 5/21/2014 7:59 PM BioFlix Activity: Cellular Respiration and Photosynthesis — Energy Flow Can you identify how energy flows through an ecosystem? To review energy flow in cellular respiration and photosynthesis, watch these BioFlix animations: Cellular Respiration and Photosynthesis. Part A – Energy flow through an ecosystem Drag the labels onto the diagram to identify how energy flows through an ecosystem. ANSWER: BioFlix Activity: Cellular Respiration and Photosynthesis — Chemical Cycling Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 5 of 13 5/21/2014 7:59 PM Can you identify how chemicals cycle in an ecosystem? To review the chemical inputs and outputs of cellular respiration and photosynthesis, watch these BioFlix animations: Cellular Respiration and Photosynthesis. Part A – Chemical cycling in an ecosystem Drag the labels onto the diagram to identify how chemicals cycle in an ecosystem. ANSWER: BioFlix Activity: Cellular Respiration — Inputs and Outputs Can you fill in the cellular respiration equation? To review cellular respiration, watch this BioFlix animation: Cellular Respiration. Part A – Cellular respiration equation Drag the labels onto the equation to identify the inputs and outputs of cellular respiration. ANSWER: Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 6 of 13 5/21/2014 7:59 PM BioFlix Activity: Population Ecology — Types of Population Growth Can you identify the different ways in which populations grow? To review types of population growth, watch this BioFlix animation: Population Ecology. Part A – Types of population growth Drag the correct label under each graph to identify the type of population growth shown. ANSWER: Concept Review: Calculating Doubling Time Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 7 of 13 5/21/2014 7:59 PM Can you calculate doubling times and growth rates for exponentially growing populations? Remember that the doubling time (in years) for an exponentially growing population is estimated by dividing 70 by the growth rate of the population (as a percentage): Doubling time (in years) = 70 / annual growth rate (%) Part A Drag the values on the left to the appropriate blanks on the right to complete the sentences. Not all values will be used. ANSWER: Concept Review: Calculating Population Growth Rates Populations grow larger from births and immigration and grow smaller from deaths and emigration. The growth rate for a population is determined by adding the birth rate and the immigration rate, and then subtracting the death rate and the emigration rate (all rates expressed as the number per 1,000 individuals per year): (birth rate + immigration rate) (death rate + emigration rate) = growth rate Positive population growth rates lead to population increases, and negative population growth rates lead to population declines. Part A Suppose you are studying a population with the following characteristics: Birth rate = 14 per 1,000/year Death rate = 6 per 1,000/year Immigration rate = 5 per 1,000/year Emigration rate = 1 per 1,000/year What is the growth rate for this population? ANSWER: Part B Suppose you are studying a population with the following characteristics: 4 per 1,000/year 12 per 1,000/year 14 per 1,000/year 26 per 1,000/year Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 8 of 13 5/21/2014 7:59 PM Birth rate = 11 per 1,000/year Death rate = 10 per 1,000/year Immigration rate = 4 per 1,000/year Emigration rate = 3 per 1,000/year What is the growth rate for this population? ANSWER: Part C Suppose you are studying a population with the following characteristics: Birth rate = 10 per 1,000/year Death rate = 12 per 1,000/year Immigration rate = 2 per 1,000/year Emigration rate = 3 per 1,000/year What is the growth rate for this population? ANSWER: Part D This question will be shown after you complete previous question(s). Part E This question will be shown after you complete previous question(s). Part F This question will be shown after you complete previous question(s). Concept Review: Levels of Ecological Organization Can you identify the example that corresponds to each level of ecological organization? Part A Drag the labels to the appropriate targets in the table. ANSWER: 0 per 1,000/year 2 per 1,000/year 14 per 1,000/year 28 per 1,000/year 3 per 1,000/year 1 per 1,000/year 17 per 1,000/year 27 per 1,000/year Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 9 of 13 5/21/2014 7:59 PM BioFlix Activity: Mechanisms of Evolution — Natural Selection: Pesticides Can you identify the process by which natural selection acts on an insect population exposed to pesticides? To review the process of natural selection, watch this BioFlix animation: Mechanisms of Evolution: Natural Selection. Part A – Natural selection: Pesticides Drag the labels onto the flowchart to place them in the correct sequence. ANSWER: Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 10 of 13 5/21/2014 7:59 PM ABC News Video: Protecting the Galapagos Islands Watch the ABC News video (2:07 minutes). Then answer the questions below. Part A Where are the Galapagos Islands located? ANSWER: Part B Which of the following sets of animals are likely to be found on the Galapagos Islands? ANSWER: near the tip of South Africa northeast of Australia along the Great Barrier Reef 600 miles west of Ecuador, near the equator in the Mediterranean Sea, as part of the Greek Islands frogs, lungfish, mountain goats tortoises, finches, blue-footed boobies ostriches, cougars, porcupines beaver, snakes, armadillos Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 11 of 13 5/21/2014 7:59 PM Part C Which species is threatening the natural wildlife on the Galapagos Islands? ANSWER: Part D The Galapagos Islands were the first place on Earth to _____. ANSWER: Part E Tourism on the Galapagos Islands is being restricted by requiring tourists to _____. ANSWER: Current Events: A Surplus Washington Could Do Without: A Capital Park’s Rapacious Deer (New York Times, 2/28/2012) Read this New York Times article and then answer the questions. A Surplus Washington Could Do Without: A Capital Park’s Rapacious Deer (2/28/2012) Registration with The New York Times provides instant access to breaking news on NYTimes.com. To register, go to http://www.nytimes.com/register. Visit http://www.nytimes.com/content/help/rights/terms/terms-of-service.html to review the current NYT Terms of Service. Part A Which of the following is true? ANSWER: Part B What predator currently feeds on deer in Rock Creek Park? humans zebra mussels Asian carp mountain lions suffer the complete extinction of all native species be declared off-limits to all humans be declared a world heritage site be invaded by human-introduced species visit each island in groups of only ten individuals at a time view the islands only from the water be escorted by trained guides at all times stay at least 100 feet away from all animals on the islands Deer have always been a problem in Rock Creek Park. Deer are not a problem in Rock Creek Park. Deer are not native to Rock Creek Park, and have been a problem since they were introduced in 1952. Deer were once absent from Rock Creek Park, and have only become a problem in the last 20 years. Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 12 of 13 5/21/2014 7:59 PM ANSWER: Part C Why isn’t the deer population controlled by hunting in Rock Creek Park? ANSWER: Part D It is hoped that the deer herd can be reduced by how much? ANSWER: Part E Which of the following is true? ANSWER: Part F Because the park is changing in response to the increasing deer population, this is an example of ______________. ANSWER: Score Summary: Your score on this assignment is 21.2%. You received 9.1 out of a possible total of 43 points. There are no predators of deer in Rock Creek Park. mountain lion coyote wolf Hunting has been attempted in the park, but the trees are too thick. Hunting is prohibited in the park. There is no public interest in hunting in the park. Deer are a protected species. one-quarter one-half three-quarters the entire herd Animals cannot be killed on federally managed public lands. Only Congress can decide to have animals killed on federally managed public lands. The federal agency in charge of management of the land in question decides if animals should be killed. Only the National Park Service can decide to have animals killed on federally managed public lands. succession artificial selection recession progression Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 13 of 13 5/21/2014 7:59 PM

Chapter 04 Homework Due: 11:59pm on Friday, May 23, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Activity: Investigating Survivorship Curves Click here to complete this activity. Then answer the questions. Part A Which of these species typically has a mortality rate that remains fairly constant over an individual’s life span? ANSWER: Correct The mortality rate of robins remains relatively constant throughout their life span. Part B Oyster populations are primarily, if not exclusively, composed of _____. ANSWER: Correct Young oysters have a very high mortality rate; older oysters have a much lower mortality rate. Thus, most oyster populations consist primarily of older individuals. Part C Which of these organisms has a survivorship curve similar to that of oysters? ANSWER: grasses oysters elephants robins humans juveniles adults prereproductive oysters larval and juvenile oysters larvae Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 1 of 13 5/21/2014 7:59 PM Correct Grasses, like oysters, have a relatively high mortality rate early in their life span, after which the mortality rate decreases. Part D Which of these organisms has a survivorship curve similar to that of humans? ANSWER: Correct The mortality rate of elephants, like that of humans, remains relatively low for much of their life span and then dramatically increases for older individuals. BioFlix Quiz: Population Ecology Watch the animation at left before answering the questions below. cats robins elephants grasses humans cats oysters grasses robins elephants Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 2 of 13 5/21/2014 7:59 PM Part A An ideal habitat with unlimited resources is associated with Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Correct Populations grow exponentially with unlimited resources. Part B The maximum population a habitat can support is its Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Correct Part C Logistic growth involves Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Both exponential growth and logistic growth. Population crashes. Exponential growth. Logistic growth. Neither exponential growth nor logistic growth. Logistic growth. Death rate. Birth rate. Carrying capacity. Exponential growth. A population crash. Population growth continuing forever. Population growth reaching carrying capacity and then speeding up. Population size decreasing to zero. Population growth slowing down as the population approaches carrying capacity. Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 3 of 13 5/21/2014 7:59 PM Correct Part D In exponential growth Hint 1. Review the animation or your Study Sheet for Population Ecology ANSWER: Correct Part E Which of the following would NOT cause population size to decrease? Hint 1. Review the animation. ANSWER: Correct An increased birth rate would cause population size to increase. BioFlix Activity: Photosynthesis — Inputs and Outputs Can you fill in the photosynthesis equation? To review photosynthesis, watch this BioFlix animation: Photosynthesis. Part A – Photosynthesis equation Drag the labels onto the equation to identify the inputs and outputs of photosynthesis. ANSWER: Population size grows more and more slowly as the population gets bigger. Population size grows faster and faster as the population gets bigger. Population size stays constant. Population growth slows as the population gets close to its carrying capacity. None of these are correct. Increased death rate A exponentially growing population outgrowing its food supply and crashing Poor weather, resulting in less food being available Increase in the number of predators Increased birth rate Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 4 of 13 5/21/2014 7:59 PM BioFlix Activity: Cellular Respiration and Photosynthesis — Energy Flow Can you identify how energy flows through an ecosystem? To review energy flow in cellular respiration and photosynthesis, watch these BioFlix animations: Cellular Respiration and Photosynthesis. Part A – Energy flow through an ecosystem Drag the labels onto the diagram to identify how energy flows through an ecosystem. ANSWER: BioFlix Activity: Cellular Respiration and Photosynthesis — Chemical Cycling Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 5 of 13 5/21/2014 7:59 PM Can you identify how chemicals cycle in an ecosystem? To review the chemical inputs and outputs of cellular respiration and photosynthesis, watch these BioFlix animations: Cellular Respiration and Photosynthesis. Part A – Chemical cycling in an ecosystem Drag the labels onto the diagram to identify how chemicals cycle in an ecosystem. ANSWER: BioFlix Activity: Cellular Respiration — Inputs and Outputs Can you fill in the cellular respiration equation? To review cellular respiration, watch this BioFlix animation: Cellular Respiration. Part A – Cellular respiration equation Drag the labels onto the equation to identify the inputs and outputs of cellular respiration. ANSWER: Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 6 of 13 5/21/2014 7:59 PM BioFlix Activity: Population Ecology — Types of Population Growth Can you identify the different ways in which populations grow? To review types of population growth, watch this BioFlix animation: Population Ecology. Part A – Types of population growth Drag the correct label under each graph to identify the type of population growth shown. ANSWER: Concept Review: Calculating Doubling Time Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 7 of 13 5/21/2014 7:59 PM Can you calculate doubling times and growth rates for exponentially growing populations? Remember that the doubling time (in years) for an exponentially growing population is estimated by dividing 70 by the growth rate of the population (as a percentage): Doubling time (in years) = 70 / annual growth rate (%) Part A Drag the values on the left to the appropriate blanks on the right to complete the sentences. Not all values will be used. ANSWER: Concept Review: Calculating Population Growth Rates Populations grow larger from births and immigration and grow smaller from deaths and emigration. The growth rate for a population is determined by adding the birth rate and the immigration rate, and then subtracting the death rate and the emigration rate (all rates expressed as the number per 1,000 individuals per year): (birth rate + immigration rate) (death rate + emigration rate) = growth rate Positive population growth rates lead to population increases, and negative population growth rates lead to population declines. Part A Suppose you are studying a population with the following characteristics: Birth rate = 14 per 1,000/year Death rate = 6 per 1,000/year Immigration rate = 5 per 1,000/year Emigration rate = 1 per 1,000/year What is the growth rate for this population? ANSWER: Part B Suppose you are studying a population with the following characteristics: 4 per 1,000/year 12 per 1,000/year 14 per 1,000/year 26 per 1,000/year Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 8 of 13 5/21/2014 7:59 PM Birth rate = 11 per 1,000/year Death rate = 10 per 1,000/year Immigration rate = 4 per 1,000/year Emigration rate = 3 per 1,000/year What is the growth rate for this population? ANSWER: Part C Suppose you are studying a population with the following characteristics: Birth rate = 10 per 1,000/year Death rate = 12 per 1,000/year Immigration rate = 2 per 1,000/year Emigration rate = 3 per 1,000/year What is the growth rate for this population? ANSWER: Part D This question will be shown after you complete previous question(s). Part E This question will be shown after you complete previous question(s). Part F This question will be shown after you complete previous question(s). Concept Review: Levels of Ecological Organization Can you identify the example that corresponds to each level of ecological organization? Part A Drag the labels to the appropriate targets in the table. ANSWER: 0 per 1,000/year 2 per 1,000/year 14 per 1,000/year 28 per 1,000/year 3 per 1,000/year 1 per 1,000/year 17 per 1,000/year 27 per 1,000/year Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 9 of 13 5/21/2014 7:59 PM BioFlix Activity: Mechanisms of Evolution — Natural Selection: Pesticides Can you identify the process by which natural selection acts on an insect population exposed to pesticides? To review the process of natural selection, watch this BioFlix animation: Mechanisms of Evolution: Natural Selection. Part A – Natural selection: Pesticides Drag the labels onto the flowchart to place them in the correct sequence. ANSWER: Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 10 of 13 5/21/2014 7:59 PM ABC News Video: Protecting the Galapagos Islands Watch the ABC News video (2:07 minutes). Then answer the questions below. Part A Where are the Galapagos Islands located? ANSWER: Part B Which of the following sets of animals are likely to be found on the Galapagos Islands? ANSWER: near the tip of South Africa northeast of Australia along the Great Barrier Reef 600 miles west of Ecuador, near the equator in the Mediterranean Sea, as part of the Greek Islands frogs, lungfish, mountain goats tortoises, finches, blue-footed boobies ostriches, cougars, porcupines beaver, snakes, armadillos Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 11 of 13 5/21/2014 7:59 PM Part C Which species is threatening the natural wildlife on the Galapagos Islands? ANSWER: Part D The Galapagos Islands were the first place on Earth to _____. ANSWER: Part E Tourism on the Galapagos Islands is being restricted by requiring tourists to _____. ANSWER: Current Events: A Surplus Washington Could Do Without: A Capital Park’s Rapacious Deer (New York Times, 2/28/2012) Read this New York Times article and then answer the questions. A Surplus Washington Could Do Without: A Capital Park’s Rapacious Deer (2/28/2012) Registration with The New York Times provides instant access to breaking news on NYTimes.com. To register, go to http://www.nytimes.com/register. Visit http://www.nytimes.com/content/help/rights/terms/terms-of-service.html to review the current NYT Terms of Service. Part A Which of the following is true? ANSWER: Part B What predator currently feeds on deer in Rock Creek Park? humans zebra mussels Asian carp mountain lions suffer the complete extinction of all native species be declared off-limits to all humans be declared a world heritage site be invaded by human-introduced species visit each island in groups of only ten individuals at a time view the islands only from the water be escorted by trained guides at all times stay at least 100 feet away from all animals on the islands Deer have always been a problem in Rock Creek Park. Deer are not a problem in Rock Creek Park. Deer are not native to Rock Creek Park, and have been a problem since they were introduced in 1952. Deer were once absent from Rock Creek Park, and have only become a problem in the last 20 years. Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 12 of 13 5/21/2014 7:59 PM ANSWER: Part C Why isn’t the deer population controlled by hunting in Rock Creek Park? ANSWER: Part D It is hoped that the deer herd can be reduced by how much? ANSWER: Part E Which of the following is true? ANSWER: Part F Because the park is changing in response to the increasing deer population, this is an example of ______________. ANSWER: Score Summary: Your score on this assignment is 21.2%. You received 9.1 out of a possible total of 43 points. There are no predators of deer in Rock Creek Park. mountain lion coyote wolf Hunting has been attempted in the park, but the trees are too thick. Hunting is prohibited in the park. There is no public interest in hunting in the park. Deer are a protected species. one-quarter one-half three-quarters the entire herd Animals cannot be killed on federally managed public lands. Only Congress can decide to have animals killed on federally managed public lands. The federal agency in charge of management of the land in question decides if animals should be killed. Only the National Park Service can decide to have animals killed on federally managed public lands. succession artificial selection recession progression Chapter 04 Homework http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 13 of 13 5/21/2014 7:59 PM

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Chapter 06 Reading Questions Due: 11:59pm on Friday, May 23, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Chapter 6 Reading Quiz Question 17 Part A Which of the following represents an example of intraspecific exploitation competition? ANSWER: Chapter 6 Reading Quiz Question 3 Part A A species’s realized niche _____. ANSWER: Chapter 6 Reading Quiz Question 2 Part A Two species of ant compete for limited resources in a front yard, until only one species is able to remain. This is an example of _____. ANSWER: Hungry and fighting for a meal, a jackal quickly consumes the carcass of a young antelope while fighting off the feeding efforts of a vulture. Two species of worker ants converge on pieces of a donut left behind from the people in the park. The leaves of the huge hickory tree overshadow the young hickory tree saplings struggling for light just below. Spotting a fresh source of grasses, the large male bison moves over to graze, pushing the smaller bison out of the way. is smaller than the fundamental niche because of the constraints of competition is broader than a species’s fundamental niche does not overlap with similar species includes environmental conditions that are not included in the fundamental niche Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 1 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 20 Part A In which of the following situations would we expect a parasite to spread the fastest? ANSWER: Chapter 6 Reading Quiz Question 6 Part A Many plants have evolved adaptations to discourage herbivore feeding. Which one of the following is an example of such coevolution between bison and prairie plants? ANSWER: Chapter 6 Reading Quiz Question 5 Part A When predators selectively prey on the old and sick members of a prey population, they _____. ANSWER: mutualism intraspecific competition the competitive exclusion principle niche differentiation concentrated hosts with slowly moving vectors widely dispersed hosts with rapidly moving vectors concentrated hosts with rapidly moving vectors widely dispersed hosts with slow-moving vectors the ability to regrow after a wildfire thorns the production of nutritious fruits longer and thicker roots Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 2 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 21 Part A Cattle egrets are large white birds that follow grazing cattle. The cattle disturb the grass and stir up insects upon which the egrets feed. The cattle do not seem to mind the birds and gain nothing from this relationship. This relationship between cattle and cattle egrets is a type of _____. ANSWER: Chapter 6 Reading Quiz Question 8 Part A Which of the following is a mutualistic relationship that has a significant effect on an entire ecological community? ANSWER: Chapter 6 Reading Quiz Question 7 Part A Which one of the following relationships would be considered a win/win? ANSWER: cause the overall health of the prey population to increase illustrate the process of prey switching increase the likelihood of parasitic infections of the prey cause the overall health of the prey population to decrease parasitism commensalism mimicry mutualism Polar bears are the top predator influencing the abundance of seals and sea lions in a region. Hermit crabs inhabit the abandoned shells of marine snails that died long ago. Fungus-plant root associations benefit most of the plants living in a prairie. Mosquitoes function as a vector in the widespread transmission of malaria to people living in Ecuador. Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 3 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 23 Part A In examining a terrestrial food web, we expect that the _____. ANSWER: Chapter 6 Reading Quiz Question 22 Part A Energy is lost as it moves from one trophic level to the next because _____. ANSWER: Chapter 6 Reading Quiz Question 11 Part A The research on the reintroduction of wolves into Yellowstone National Park reveals that in this ecosystem, wolves represent _____. ANSWER: mutualism predation parasitism commensalism biomass of primary consumers exceeds the biomass of producers number of secondary consumers exceeds the number of producers biomass of primary consumers exceeds the biomass of secondary consumers number of tertiary consumers exceeds the number of secondary consumers one trophic level does not consume the entire trophic level below it some of the calories consumed drive cellular activities and do not add mass some ingested materials are undigested and eliminated All of the listed responses are correct. Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 4 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 10 Part A Overhunting of deer followed by a very difficult winter caused the deer population on an island to drop by 80%. In the next two years, visitors to the island were surprised to see many young trees sprouting up at the edges of the forest. This change in the number of saplings as a result of the decline of the deer population represents _____. ANSWER: Chapter 6 Reading Quiz Question 24 Part A The May 18, 1980, eruption of Mount Saint Helens blasted away soil and produced massive mudflows that scoured the adjacent region down to bare rock. Pumice rock that covered the area is eroding down to smaller gravel. This situation represents _____. ANSWER: Chapter 6 Reading Quiz Question 15 Part A In some ecosystems, succession increases the chance of disturbance. In these ecosystems, _____. a keystone producer a keystone herbivore a vital primary consumer a keystone predator a trophic cascade a decline in trophic level efficiency the emergence of a new ecological community a loss of a trophic level from a food web primary succession with the removal of all ecological legacies secondary succession with the removal of all ecological legacies secondary succession with several ecological legacies primary succession with several ecological legacies Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 5 of 7 5/21/2014 8:01 PM ANSWER: Chapter 6 Reading Quiz Question 12 Part A A forest is logged, leaving behind the seeds and saplings of many shrubs and trees. These seeds and saplings represent _____. ANSWER: Chapter 6 Reading Quiz Question 13 Part A During primary succession, populations of different species replace one another over time because of _____. ANSWER: Chapter 6 Reading Quiz Question 14 Part A Which one of the following represents a climax community in southern Alaska? ANSWER: ecosystems begin again with primary succession climax communities are expected climax communities may not occur disturbances usually result in virtually no ecological legacy ecological legacies a climax community primary succession pioneer species migration facilitation competition All of the listed responses are correct. Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 6 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 9 Part A In general, _____. ANSWER: Score Summary: Your score on this assignment is 0.0%. You received 0 out of a possible total of 19 points. the group of species associated with a white spruce forest lichens and mosses that colonize exposed rock birch and alder trees herbs and a few low shrubs that replace lichens and mosses food webs usually have 8-10 trophic levels food webs are interconnected food chains food chains consist of many interrelated food webs food webs consist of either consumers or producers Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 7 of 7 5/21/2014 8:01 PM

Chapter 06 Reading Questions Due: 11:59pm on Friday, May 23, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Chapter 6 Reading Quiz Question 17 Part A Which of the following represents an example of intraspecific exploitation competition? ANSWER: Chapter 6 Reading Quiz Question 3 Part A A species’s realized niche _____. ANSWER: Chapter 6 Reading Quiz Question 2 Part A Two species of ant compete for limited resources in a front yard, until only one species is able to remain. This is an example of _____. ANSWER: Hungry and fighting for a meal, a jackal quickly consumes the carcass of a young antelope while fighting off the feeding efforts of a vulture. Two species of worker ants converge on pieces of a donut left behind from the people in the park. The leaves of the huge hickory tree overshadow the young hickory tree saplings struggling for light just below. Spotting a fresh source of grasses, the large male bison moves over to graze, pushing the smaller bison out of the way. is smaller than the fundamental niche because of the constraints of competition is broader than a species’s fundamental niche does not overlap with similar species includes environmental conditions that are not included in the fundamental niche Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 1 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 20 Part A In which of the following situations would we expect a parasite to spread the fastest? ANSWER: Chapter 6 Reading Quiz Question 6 Part A Many plants have evolved adaptations to discourage herbivore feeding. Which one of the following is an example of such coevolution between bison and prairie plants? ANSWER: Chapter 6 Reading Quiz Question 5 Part A When predators selectively prey on the old and sick members of a prey population, they _____. ANSWER: mutualism intraspecific competition the competitive exclusion principle niche differentiation concentrated hosts with slowly moving vectors widely dispersed hosts with rapidly moving vectors concentrated hosts with rapidly moving vectors widely dispersed hosts with slow-moving vectors the ability to regrow after a wildfire thorns the production of nutritious fruits longer and thicker roots Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 2 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 21 Part A Cattle egrets are large white birds that follow grazing cattle. The cattle disturb the grass and stir up insects upon which the egrets feed. The cattle do not seem to mind the birds and gain nothing from this relationship. This relationship between cattle and cattle egrets is a type of _____. ANSWER: Chapter 6 Reading Quiz Question 8 Part A Which of the following is a mutualistic relationship that has a significant effect on an entire ecological community? ANSWER: Chapter 6 Reading Quiz Question 7 Part A Which one of the following relationships would be considered a win/win? ANSWER: cause the overall health of the prey population to increase illustrate the process of prey switching increase the likelihood of parasitic infections of the prey cause the overall health of the prey population to decrease parasitism commensalism mimicry mutualism Polar bears are the top predator influencing the abundance of seals and sea lions in a region. Hermit crabs inhabit the abandoned shells of marine snails that died long ago. Fungus-plant root associations benefit most of the plants living in a prairie. Mosquitoes function as a vector in the widespread transmission of malaria to people living in Ecuador. Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 3 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 23 Part A In examining a terrestrial food web, we expect that the _____. ANSWER: Chapter 6 Reading Quiz Question 22 Part A Energy is lost as it moves from one trophic level to the next because _____. ANSWER: Chapter 6 Reading Quiz Question 11 Part A The research on the reintroduction of wolves into Yellowstone National Park reveals that in this ecosystem, wolves represent _____. ANSWER: mutualism predation parasitism commensalism biomass of primary consumers exceeds the biomass of producers number of secondary consumers exceeds the number of producers biomass of primary consumers exceeds the biomass of secondary consumers number of tertiary consumers exceeds the number of secondary consumers one trophic level does not consume the entire trophic level below it some of the calories consumed drive cellular activities and do not add mass some ingested materials are undigested and eliminated All of the listed responses are correct. Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 4 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 10 Part A Overhunting of deer followed by a very difficult winter caused the deer population on an island to drop by 80%. In the next two years, visitors to the island were surprised to see many young trees sprouting up at the edges of the forest. This change in the number of saplings as a result of the decline of the deer population represents _____. ANSWER: Chapter 6 Reading Quiz Question 24 Part A The May 18, 1980, eruption of Mount Saint Helens blasted away soil and produced massive mudflows that scoured the adjacent region down to bare rock. Pumice rock that covered the area is eroding down to smaller gravel. This situation represents _____. ANSWER: Chapter 6 Reading Quiz Question 15 Part A In some ecosystems, succession increases the chance of disturbance. In these ecosystems, _____. a keystone producer a keystone herbivore a vital primary consumer a keystone predator a trophic cascade a decline in trophic level efficiency the emergence of a new ecological community a loss of a trophic level from a food web primary succession with the removal of all ecological legacies secondary succession with the removal of all ecological legacies secondary succession with several ecological legacies primary succession with several ecological legacies Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 5 of 7 5/21/2014 8:01 PM ANSWER: Chapter 6 Reading Quiz Question 12 Part A A forest is logged, leaving behind the seeds and saplings of many shrubs and trees. These seeds and saplings represent _____. ANSWER: Chapter 6 Reading Quiz Question 13 Part A During primary succession, populations of different species replace one another over time because of _____. ANSWER: Chapter 6 Reading Quiz Question 14 Part A Which one of the following represents a climax community in southern Alaska? ANSWER: ecosystems begin again with primary succession climax communities are expected climax communities may not occur disturbances usually result in virtually no ecological legacy ecological legacies a climax community primary succession pioneer species migration facilitation competition All of the listed responses are correct. Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 6 of 7 5/21/2014 8:01 PM Chapter 6 Reading Quiz Question 9 Part A In general, _____. ANSWER: Score Summary: Your score on this assignment is 0.0%. You received 0 out of a possible total of 19 points. the group of species associated with a white spruce forest lichens and mosses that colonize exposed rock birch and alder trees herbs and a few low shrubs that replace lichens and mosses food webs usually have 8-10 trophic levels food webs are interconnected food chains food chains consist of many interrelated food webs food webs consist of either consumers or producers Chapter 06 Reading Questions http://session.masteringenvironmentalscience.com/myct/assignmentPrintV… 7 of 7 5/21/2014 8:01 PM

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____ types of asphalt paving are in common use. Two Four Three Five ___ is the act of remodeling the existing land form to provide a level area for a structure, create circulation paths, and create drainage and landscape features. Grading Excavating Sheeting Caissoning ____ foundations use long wood, concrete, or steel piles that are driven into the earth. Pile Mat Spread Caisson ____ hammers use a heavy weight lifted up vertical rails called leads. Diesel Vibratory Single-acting steam Drop ____ of soil refers to increasing its density by mechanically forcing the soil particles closer together. Blending Compaction Shaking Consolidation ____ are temporary watertight enclosures used either in water-bearing soil or directly in water. Cofferdams Caissons Slurries Sheet pilings The ____ was developed by the U.S. Army Corps of Engineers to classify soils for use in roads, embankments, and foundations. Unified Soil Classification System American Association of State Highway and Transportation Officials System Chicago Center for Green Technologies American Society of Testing and Materials ____ piles utilize heavy-gauge steel pipes that are driven with an open end. H Precast concrete Pipe Timber A ____ test ascertains the consistency of a soil sample near the plastic limit. dry strength toughness soil coarseness shaking ____ techniques involve lowering the level of subsurface water on a site to allow excavation to occur in a dry and stable environment. Underpinning Excavating Dewatering Sheeting Clays and silty clay soils can be stabilized through the addition of ____, which produces a chemical reaction. calcium carbon ore lime ____ foundations are reinforced concrete slabs several feet in thickness that cover the entire footprint of a building. Pile Mat Spread Caisson ____, in the form of sheet piling, lagging, and slurry walls, is used to hold up the face of an excavation. Excavating Grading Anchoring Sheeting Predominantly granular soils that have minute amounts of clay particles can be stabilized by blending them with ____. Portland cement asphalt rock salt lime A ____ foundation is a pier that is drilled into the earth, filled with the required reinforcing steel, and poured with concrete. caisson spread mat pile

____ types of asphalt paving are in common use. Two Four Three Five ___ is the act of remodeling the existing land form to provide a level area for a structure, create circulation paths, and create drainage and landscape features. Grading Excavating Sheeting Caissoning ____ foundations use long wood, concrete, or steel piles that are driven into the earth. Pile Mat Spread Caisson ____ hammers use a heavy weight lifted up vertical rails called leads. Diesel Vibratory Single-acting steam Drop ____ of soil refers to increasing its density by mechanically forcing the soil particles closer together. Blending Compaction Shaking Consolidation ____ are temporary watertight enclosures used either in water-bearing soil or directly in water. Cofferdams Caissons Slurries Sheet pilings The ____ was developed by the U.S. Army Corps of Engineers to classify soils for use in roads, embankments, and foundations. Unified Soil Classification System American Association of State Highway and Transportation Officials System Chicago Center for Green Technologies American Society of Testing and Materials ____ piles utilize heavy-gauge steel pipes that are driven with an open end. H Precast concrete Pipe Timber A ____ test ascertains the consistency of a soil sample near the plastic limit. dry strength toughness soil coarseness shaking ____ techniques involve lowering the level of subsurface water on a site to allow excavation to occur in a dry and stable environment. Underpinning Excavating Dewatering Sheeting Clays and silty clay soils can be stabilized through the addition of ____, which produces a chemical reaction. calcium carbon ore lime ____ foundations are reinforced concrete slabs several feet in thickness that cover the entire footprint of a building. Pile Mat Spread Caisson ____, in the form of sheet piling, lagging, and slurry walls, is used to hold up the face of an excavation. Excavating Grading Anchoring Sheeting Predominantly granular soils that have minute amounts of clay particles can be stabilized by blending them with ____. Portland cement asphalt rock salt lime A ____ foundation is a pier that is drilled into the earth, filled with the required reinforcing steel, and poured with concrete. caisson spread mat pile

____ types of asphalt paving are in common use. Two … Read More...
1-Two notions serve as the basis for all torts: wrongs and compensation. True False 2-The goal of tort law is to put a defendant in the position that he or she would have been in had the tort occurred to the defendant. True False 3-Hayley is injured in an accident precipitated by Isolde. Hayley files a tort action against Isolde, seeking to recover for the damage suffered. Damages that are intended to compensate or reimburse a plaintiff for actual losses are: compensatory damages. reimbursement damages. actual damages. punitive damages. 4-Ladd throws a rock intending to hit Minh but misses and hits Nasir instead. On the basis of the tort of battery, Nasir can sue: Ladd. Minh. the rightful owner of the rock. no one. 4-Luella trespasses on Merchandise Mart’s property. Through the use of reasonable force, Merchandise Mart’s security guard detains Luella until the police arrive. Merchandise Mart is liable for: assault. battery. false imprisonment. none of the choice 6-The extreme risk of an activity is a defense against imposing strict liability. True False 7-Misrepresentation in an ad is enough to show an intent to induce the reliance of anyone who may use the product. True False 8-Luke is playing a video game on a defective disk that melts in his game player, starting a fire that injures his hands. Luke files a suit against Mystic Maze, Inc., the game’s maker under the doctrine of strict liability. A significant application of this doctrine is in the area of: cyber torts. intentional torts. product liability. unintentional torts 9-More than two hundred years ago, the Declaration of Independence recognized the importance of protecting creative works. True False 10-n 2014, Cloud Computing Corporation registers its trademark as provided by federal law. After the first renewal, this registration: is renewable every ten years. is renewable every twenty years. runs for life of the corporation plus seventy years. runs forever. 11-Wendy works as a weather announcer for a TV station under the character name Weather Wendy. Wendy can register her character’s name as: a certification mark. a trade name. a service mark. none of the choices 12-Much of the material on the Internet, including software and database information, is not copyrighted. True False 13-In a criminal case, the state must prove its case by a preponderance of the evidence. True False 14-Under the Fourth Amendmentt, general searches through a person’s belongings are permissible. True False 15-Maura enters a gas station and points a gun at the clerk Nate. She then forces Nate to open the cash register and give her all the money. Maura can be charged with: burglary. robbery. larceny. receiving stolen property. 16-Reno, driving while intoxicated, causes a car accident that results in the death of Santo. Reno is arrested and charged with a felony. A felony is a crime punishable by death or imprisonment for: any period of time. more than one year. more than six months. more than ten days. 17-Corporate officers and directors may be held criminally liable for the actions of employees under their supervision. True False 18-Sal assures Tom that she will deliver a truckload of hay to his cattle ranch. A person’s declaration to do a certain act is part of the definition of: an expectation. a moral obligation. a prediction. a promise. 19-Lark promises to buy Mac’s used textbook for $60. Lark is: an offeror. an offeree a promisee. a promisor. 20-Casey offers to sell a certain used forklift to DIY Lumber Outlet, but Casey dies before DIY accepts. Most likely, Casey’s death: did not affect the offer. shortened the time of the offer but did not terminated it. extended the time of the offer. terminated the offer.

1-Two notions serve as the basis for all torts: wrongs and compensation. True False 2-The goal of tort law is to put a defendant in the position that he or she would have been in had the tort occurred to the defendant. True False 3-Hayley is injured in an accident precipitated by Isolde. Hayley files a tort action against Isolde, seeking to recover for the damage suffered. Damages that are intended to compensate or reimburse a plaintiff for actual losses are: compensatory damages. reimbursement damages. actual damages. punitive damages. 4-Ladd throws a rock intending to hit Minh but misses and hits Nasir instead. On the basis of the tort of battery, Nasir can sue: Ladd. Minh. the rightful owner of the rock. no one. 4-Luella trespasses on Merchandise Mart’s property. Through the use of reasonable force, Merchandise Mart’s security guard detains Luella until the police arrive. Merchandise Mart is liable for: assault. battery. false imprisonment. none of the choice 6-The extreme risk of an activity is a defense against imposing strict liability. True False 7-Misrepresentation in an ad is enough to show an intent to induce the reliance of anyone who may use the product. True False 8-Luke is playing a video game on a defective disk that melts in his game player, starting a fire that injures his hands. Luke files a suit against Mystic Maze, Inc., the game’s maker under the doctrine of strict liability. A significant application of this doctrine is in the area of: cyber torts. intentional torts. product liability. unintentional torts 9-More than two hundred years ago, the Declaration of Independence recognized the importance of protecting creative works. True False 10-n 2014, Cloud Computing Corporation registers its trademark as provided by federal law. After the first renewal, this registration: is renewable every ten years. is renewable every twenty years. runs for life of the corporation plus seventy years. runs forever. 11-Wendy works as a weather announcer for a TV station under the character name Weather Wendy. Wendy can register her character’s name as: a certification mark. a trade name. a service mark. none of the choices 12-Much of the material on the Internet, including software and database information, is not copyrighted. True False 13-In a criminal case, the state must prove its case by a preponderance of the evidence. True False 14-Under the Fourth Amendmentt, general searches through a person’s belongings are permissible. True False 15-Maura enters a gas station and points a gun at the clerk Nate. She then forces Nate to open the cash register and give her all the money. Maura can be charged with: burglary. robbery. larceny. receiving stolen property. 16-Reno, driving while intoxicated, causes a car accident that results in the death of Santo. Reno is arrested and charged with a felony. A felony is a crime punishable by death or imprisonment for: any period of time. more than one year. more than six months. more than ten days. 17-Corporate officers and directors may be held criminally liable for the actions of employees under their supervision. True False 18-Sal assures Tom that she will deliver a truckload of hay to his cattle ranch. A person’s declaration to do a certain act is part of the definition of: an expectation. a moral obligation. a prediction. a promise. 19-Lark promises to buy Mac’s used textbook for $60. Lark is: an offeror. an offeree a promisee. a promisor. 20-Casey offers to sell a certain used forklift to DIY Lumber Outlet, but Casey dies before DIY accepts. Most likely, Casey’s death: did not affect the offer. shortened the time of the offer but did not terminated it. extended the time of the offer. terminated the offer.

1-Two notions serve as the basis for all torts: wrongs … Read More...
Essay – Athlete’s high salaries. Should they be paid that amount or not?

Essay – Athlete’s high salaries. Should they be paid that amount or not?

Athlete’s high salaries: Should they be paid that amount or … Read More...
A population of Ladon dragons has a birth rate of 2.4 individual / and a death rate of 2.2 individual / (individual x year ). i. what is the specific rate of change (r) ?, ii. Based your answer from part (i), is the population growing , declining , or remaining constant ? iii. on the wondering Rock Mountain , the population is presently 49 . what will the population be in 10 years? iv. if the carrying capacity were 105 on the wondering Rock Mountain , what would the population be in 10 years ( using the logistic model ) ?

A population of Ladon dragons has a birth rate of 2.4 individual / and a death rate of 2.2 individual / (individual x year ). i. what is the specific rate of change (r) ?, ii. Based your answer from part (i), is the population growing , declining , or remaining constant ? iii. on the wondering Rock Mountain , the population is presently 49 . what will the population be in 10 years? iv. if the carrying capacity were 105 on the wondering Rock Mountain , what would the population be in 10 years ( using the logistic model ) ?

5 { GRAVITATION Last Updated: July 16, 2012 Problem List 5.1 Total mass of a shell 5.2 Tunnel through the moon 5.3 Gravitational eld above the center of a thin hoop 5.4 Gravitational force near a metal-cored planet surrounded by a gaseous cloud 5.5 Sphere with linearly increasing mass density 5.6 Jumping o Vesta 5.7 Gravitational force between two massive rods 5.8 Potential energy { Check your answer! 5.9 Ways of solving gravitational problems 5.10 Rod with linearly increasing mass density 5.11 Sphere with constant internal gravitational eld 5.12 Throwing a rock o the moon These problems are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Un- ported License. Please share and/or modify. Back to Problem List 1 5 { GRAVITATION Last Updated: July 16, 2012 5.1 Total mass of a shell Given: Marino { Fall 2011 Consider a spherical shell that extends from r = R to r = 2R with a non-uniform density (r) = 0r. What is the total mass of the shell? Back to Problem List 2 5 { GRAVITATION Last Updated: July 16, 2012 5.2 Tunnel through the moon Given: Marino { Fall 2011 Imagine that NASA digs a straight tunnel through the center of the moon (see gure) to access the Moon’s 3He deposits. An astronaut places a rock in the tunnel at the surface of the moon, and releases it (from rest). Show that the rock obeys the force law for a mass connected to a spring. What is the spring constant? Find the oscillation period for this motion if you assume that Moon has a mass of 7.351022 kg and a radius of 1.74106 m. Assume the moon’s density is uniform throughout its volume, and ignore the moon’s rotation. Given: Pollock { Spring 2011 Imagine (in a parallel universe of unlimited budgets) that NASA digs a straight tunnel through the center of the moon (see gure). A robot place a rock in the tunnel at position r = r0 from the center of the moon, and releases it (from rest). Use Newton’s second law to write the equation of motion of the rock and solve for r(t). Explain in words the rock’s motion. Does the rock return to its initial position at any later time? If so, how long does it takes to return to it? (Give a formula, and a number.) Assume the moon’s density is uniform throughout its volume, and ignore the moon’s rotation. Given: Pollock { Spring 2012 Now lets consider our (real) planet Earth, with total mass M and radius R which we will approximate as a uniform mass density, (r) = 0. (a) Neglecting rotational and frictional e ects, show that a particle dropped into a hole drilled straight through the center of the earth all the way to the far side will oscillate between the two endpoints. (Hint: you will need to set up, and solve, an ODE for the motion) (b) Find the period of the oscillation of this motion. Get a number (in minutes) as a nal result, using data for the earth’s size and mass. (How does that compare to ying to Perth and back?!) Extra Credit: OK, even with unlimited budgets, digging a tunnel through the center of the earth is preposterous. But, suppose instead that the tunnel is a straight-line \chord” through the earth, say directly from New York to Los Angeles. Show that your nal answer for the time taken does not depend on the location of that chord! This is rather remarkable – look again at the time for a free-fall trip (no energy required, except perhaps to compensate for friction) How long would that trip take? Could this work?! Back to Problem List 3 5 { GRAVITATION Last Updated: July 16, 2012 5.3 Gravitational eld above the center of a thin hoop Given: Pollock { Spring 2011, Spring 2012 Consider a very (in nitesimally!) thin but massive loop, radius R (total mass M), centered around the origin, sitting in the x-y plane. Assume it has a uniform linear mass density  (which has units of kg/m) all around it. (So, it’s like a skinny donut that is mostly hole, centered around the z-axis) (a) What is  in terms of M and R? What is the direction of the gravitational eld generated by this mass distribution at a point in space a distance z above the center of the donut, i.e. at (0; 0; z) Explain your reasoning for the direction carefully, try not to simply \wave your hands.” (The answer is extremely intuitive, but can you justify that it is correct?) (b) Compute the gravitational eld, ~g, at the point (0; 0; z) by directly integrating Newton’s law of gravity, summing over all in nitesimal \chunks” of mass along the loop. (c) Compute the gravitational potential at the point (0; 0; z) by directly integrating ?Gdm=r, sum- ming over all in nitesimal \chunks” dm along the loop. Then, take the z-component of the gradient of this potential to check that you agree with your result from the previous part. (d) In the two separate limits z << R and z >> R, Taylor expand your g- eld (in the z-direction)out only to the rst non-zero term, and convince us that both limits make good physical sense. (e) Can you use Gauss’ law to gure out the gravitational potential at the point (0; 0; z)? (If so, do it and check your previous answers. If not, why not?) Extra credit: If you place a small mass a small distance z away from the center, use your Taylor limit for z << R above to write a simple ODE for the equation of motion. Solve it, and discuss the motion Back to Problem List 4 5 { GRAVITATION Last Updated: July 16, 2012 5.4 Gravitational force near a metal-cored planet surrounded by a gaseous cloud Given: Pollock { Spring 2011 Jupiter is composed of a dense spherical core (of liquid metallic hydrogen!) of radius Rc. It is sur- rounded by a spherical cloud of gaseous hydrogen of radius Rg, where Rg > Rc. Let’s assume that the core is of uniform density c and the gaseous cloud is also of uniform density g. What is the gravitational force on an object of mass m that is located at a radius r from the center of Jupiter? Note that you must consider the cases where the object is inside the core, within the gas layer, and outside of the planet. Back to Problem List 5 5 { GRAVITATION Last Updated: July 16, 2012 5.5 Sphere with linearly increasing mass density Given: Pollock { Spring 2011 A planet of mass M and radius R has a nonuniform density that varies with r, the distance from the center according to  = Ar for 0  r  R. (a) What is the constant A in terms of M and R? Does this density pro le strike you as physically plausible, or is just designed as a mathematical exercise? (Brie y, explain) (b) Determine the gravitational force on a satellite of mass m orbiting this planet. In words, please outline the method you plan to use for your solution. (Use the easiest method you can come up with!) In your calculation, you will need to argue that the magnitude of ~g(r; ; ) depends only on r. Be very explicit about this – how do you know that it doesn’t, in fact, depend on  or ? (c) Determine the gravitational force felt by a rock of mass m inside the planet, located at radius r < R. (If the method you use is di erent than in part b, explain why you switched. If not, just proceed!) Explicitly check your result for this part by considering the limits r ! 0 and r ! R. Back to Problem List 6 5 { GRAVITATION Last Updated: July 16, 2012 5.6 Jumping o Vesta Given: Pollock { Spring 2011 You are stranded on the surface of the asteroid Vesta. If the mass of the asteroid is M and its radius is R, how fast would you have to jump o its surface to be able to escape from its gravitational eld? (Your estimate should be based on parameters that characterize the asteroid, not parameters that describe your jumping ability.) Given your formula, look up the approximate mass and radius of the asteroid Vesta 3 and determine a numerical value of the escape velocity. Could you escape in this way? (Brie y, explain) If so, roughly how big in radius is the maximum the asteroid could be, for you to still escape this way? If not, estimate how much smaller an asteroid you would need, to escape from it in this way? Figure 1: Back to Problem List 7 5 { GRAVITATION Last Updated: July 16, 2012 5.7 Gravitational force between two massive rods Given: Pollock { Spring 2011 Consider two identical uniform rods of length L and mass m lying along the same line and having their closest points separated by a distance d as shown in the gure (a) Calculate the mutual force between these rods, both its direction and magnitude. (b) Now do several checks. First, make sure the units worked out (!) The, nd the magnitude of the force in the limit L ! 0. What do you expect? Brie y, discuss. Lastly, nd the magnitude of the force in the limit d ! 1 ? Again, is it what you expect? Brie y, discuss. Figure 2: Given: Pollock { Spring 2012 Determining the gravitational force between two rods: (a) Consider a thin, uniform rod of mass m and length L (and negligible other dimensions) lying on the x axis (from x=-L to 0), as shown in g 1a. Derive a formula for the gravitational eld \g" at any arbitrary point x to the right of the origin (but still on the x-axis!) due to this rod. (b) Now suppose a second rod of length L and mass m sits on the x axis as shown in g 1b, with the left edge a distance \d" away. Calculate the mutual gravitational force between these rods. (c) Let's do some checks! Show that the units work out in parts a and b. Find the magnitude of the force in part a, in the limit x >> L: What do you expect? Brie y, discuss! Finally, verify that your answer to part b gives what you expect in the limit d >> L. ( Hint: This is a bit harder! You need to consistently expand everything to second order, not just rst, because of some interesting cancellations) Fig 1a Fig 1b L m +x x=0 L x=0 x=d m Fig 1a Fig 1b L m +x x=0 L +x x=0 x=d L m m Back to Problem List 8 5 { GRAVITATION Last Updated: July 16, 2012 5.8 Potential energy { Check your answer! Given: Pollock { Spring 2011 On the last exam, we had a problem with a at ring, uniform mass per unit area of , inner radius of R, outer radius of 2R. A satellite (mass m) sat a distance z above the center of the ring. We asked for the gravitational potential energy, and the answer was U(z) = ?2Gm( p 4R2 + z2 ? p R2 + z2) (1) (a) If you are far from the disk (on the z axis), what do you expect for the formula for U(z)? (Don’t say \0″ – as usual, we want the functional form of U(z) as you move far away. Also, explicitly state what we mean by \far away”. (Please don’t compare something with units to something without units!) (b) Show explicitly that the formula above does indeed give precisely the functional dependence you expect. Back to Problem List 9 5 { GRAVITATION Last Updated: July 16, 2012 5.9 Ways of solving gravitational problems Given: Pollock { Spring 2011, Spring 2012 Infinite cylinder ρ=cr x z (a) Half-infinite line mass, uniform linear mass density, λ x (b) R z  P Figure 3: (a) An in nite cylinder of radius R centered on the z-axis, with non-uniform volume mass density  = cr, where r is the radius in cylindrical coordinates. (b) A half-in nite line of mass on the x-axis extending from x = 0 to x = +1, with uniform linear mass density . There are two general methods we use to solve gravitational problems (i.e. nd ~g given some distribution of mass). (a) Describe these two methods. We claim one of these methods is easiest to solve for ~g of mass distribution (a) above, and the other method is easiest to solve for ~g of the mass distribution (b) above. Which method goes with which mass distribution? Please justify your answer. (b) Find ~g of the mass distribution (a) above for any arbitrary point outside the cylinder. (c) Find the x component of the gravitational acceleration, gx, generated by the mass distribution labeled (b) above, at a point P a given distance z up the positive z-axis (as shown). Back to Problem List 10 5 { GRAVITATION Last Updated: July 16, 2012 5.10 Rod with linearly increasing mass density Given: Pollock { Spring 2012 Consider a very (in nitesimally!) thin but massive rod, length L (total mass M), centered around the origin, sitting along the x-axis. (So the left end is at (-L/2, 0,0) and the right end is at (+L/2,0,0) Assume the mass density  (which has units of kg/m)is not uniform, but instead varies linearly with distance from the origin, (x) = cjxj. (a) What is that constant \c” in terms of M and L? What is the direction of the gravitational eld generated by this mass distribution at a point in space a distance z above the center of the rod, i.e. at (0; 0; z) Explain your reasoning for the direction carefully, try not to simply \wave your hands.” (The answer is extremely intuitive, but can you justify that it is correct?) (b) Compute the gravitational eld, ~g, at the point (0; 0; z) by directly integrating Newton’s law of gravity, summing over all in nitesimal \chunks” of mass along the rod. (c) Compute the gravitational potential at the point (0; 0; z) by directly integrating ?Gdm=r, sum- ming over all in nitesimal \chunks” dm along the rod. Then, take the z-component of the gradient of this potential to check that you agree with your result from the previous part. (d) In the limit of large z what do you expect for the functional form for gravitational potential? (Hint: Don’t just say it goes to zero! It’s a rod of mass M, when you’re far away what does it look like? How does it go to zero?) What does \large z” mean here? Use the binomial (or Taylor) expansion to verify that your formula does indeed give exactly what you expect. (Hint: you cannot Taylor expand in something BIG, you have to Taylor expand in something small.) (e) Can you use Gauss’ law to gure out the gravitational potential at the point (0; 0; z)? (If so, do it and check your previous answers. If not, why not?) Back to Problem List 11 5 { GRAVITATION Last Updated: July 16, 2012 5.11 Sphere with constant internal gravitational eld Given: Pollock { Spring 2012 (a) Imagine a planet of total mass M and radius R which has a nonuniform mass density that varies just with r, the distance from the center. For this (admittedly very unusual!) planet, suppose the gravitational eld strength inside the planet turns out to be independent of the radial distance within the sphere. Find the function describing the mass density  = (r) of this planet. (Your nal answer should be written in terms of the given constants.) (b) Now, determine the gravitational force on a satellite of mass m orbiting this planet at distance r > R. (Use the easiest method you can come up with!) Explain your work in words as well as formulas. For instance, in your calculation, you will need to argue that the magnitude of ~g(r; ; ) depends only on r. Be explicit about this – how do you know that it doesn’t, in fact, depend on  or ? (c) As a nal check, explicitly show that your solutions inside and outside the planet (parts a and b) are consistent when r = R. Please also comment on whether this density pro le strikes you as physically plausible, or is it just designed as a mathematical exercise? Defend your reasoning. Back to Problem List 12 5 { GRAVITATION Last Updated: July 16, 2012 5.12 Throwing a rock o the moon Given: Pollock { Spring 2012 Assuming that asteroids have roughly the same mass density as the moon, make an estimate of the largest asteroid that an astronaut could be standing on, and still have a chance of throwing a small object (with their arms, no machinery!) so that it completely escapes the asteroid’s gravitational eld. (This minimum speed is called \escape velocity”) Is the size you computed typical for asteroids in our solar system? Back to Problem List 13

5 { GRAVITATION Last Updated: July 16, 2012 Problem List 5.1 Total mass of a shell 5.2 Tunnel through the moon 5.3 Gravitational eld above the center of a thin hoop 5.4 Gravitational force near a metal-cored planet surrounded by a gaseous cloud 5.5 Sphere with linearly increasing mass density 5.6 Jumping o Vesta 5.7 Gravitational force between two massive rods 5.8 Potential energy { Check your answer! 5.9 Ways of solving gravitational problems 5.10 Rod with linearly increasing mass density 5.11 Sphere with constant internal gravitational eld 5.12 Throwing a rock o the moon These problems are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Un- ported License. Please share and/or modify. Back to Problem List 1 5 { GRAVITATION Last Updated: July 16, 2012 5.1 Total mass of a shell Given: Marino { Fall 2011 Consider a spherical shell that extends from r = R to r = 2R with a non-uniform density (r) = 0r. What is the total mass of the shell? Back to Problem List 2 5 { GRAVITATION Last Updated: July 16, 2012 5.2 Tunnel through the moon Given: Marino { Fall 2011 Imagine that NASA digs a straight tunnel through the center of the moon (see gure) to access the Moon’s 3He deposits. An astronaut places a rock in the tunnel at the surface of the moon, and releases it (from rest). Show that the rock obeys the force law for a mass connected to a spring. What is the spring constant? Find the oscillation period for this motion if you assume that Moon has a mass of 7.351022 kg and a radius of 1.74106 m. Assume the moon’s density is uniform throughout its volume, and ignore the moon’s rotation. Given: Pollock { Spring 2011 Imagine (in a parallel universe of unlimited budgets) that NASA digs a straight tunnel through the center of the moon (see gure). A robot place a rock in the tunnel at position r = r0 from the center of the moon, and releases it (from rest). Use Newton’s second law to write the equation of motion of the rock and solve for r(t). Explain in words the rock’s motion. Does the rock return to its initial position at any later time? If so, how long does it takes to return to it? (Give a formula, and a number.) Assume the moon’s density is uniform throughout its volume, and ignore the moon’s rotation. Given: Pollock { Spring 2012 Now lets consider our (real) planet Earth, with total mass M and radius R which we will approximate as a uniform mass density, (r) = 0. (a) Neglecting rotational and frictional e ects, show that a particle dropped into a hole drilled straight through the center of the earth all the way to the far side will oscillate between the two endpoints. (Hint: you will need to set up, and solve, an ODE for the motion) (b) Find the period of the oscillation of this motion. Get a number (in minutes) as a nal result, using data for the earth’s size and mass. (How does that compare to ying to Perth and back?!) Extra Credit: OK, even with unlimited budgets, digging a tunnel through the center of the earth is preposterous. But, suppose instead that the tunnel is a straight-line \chord” through the earth, say directly from New York to Los Angeles. Show that your nal answer for the time taken does not depend on the location of that chord! This is rather remarkable – look again at the time for a free-fall trip (no energy required, except perhaps to compensate for friction) How long would that trip take? Could this work?! Back to Problem List 3 5 { GRAVITATION Last Updated: July 16, 2012 5.3 Gravitational eld above the center of a thin hoop Given: Pollock { Spring 2011, Spring 2012 Consider a very (in nitesimally!) thin but massive loop, radius R (total mass M), centered around the origin, sitting in the x-y plane. Assume it has a uniform linear mass density  (which has units of kg/m) all around it. (So, it’s like a skinny donut that is mostly hole, centered around the z-axis) (a) What is  in terms of M and R? What is the direction of the gravitational eld generated by this mass distribution at a point in space a distance z above the center of the donut, i.e. at (0; 0; z) Explain your reasoning for the direction carefully, try not to simply \wave your hands.” (The answer is extremely intuitive, but can you justify that it is correct?) (b) Compute the gravitational eld, ~g, at the point (0; 0; z) by directly integrating Newton’s law of gravity, summing over all in nitesimal \chunks” of mass along the loop. (c) Compute the gravitational potential at the point (0; 0; z) by directly integrating ?Gdm=r, sum- ming over all in nitesimal \chunks” dm along the loop. Then, take the z-component of the gradient of this potential to check that you agree with your result from the previous part. (d) In the two separate limits z << R and z >> R, Taylor expand your g- eld (in the z-direction)out only to the rst non-zero term, and convince us that both limits make good physical sense. (e) Can you use Gauss’ law to gure out the gravitational potential at the point (0; 0; z)? (If so, do it and check your previous answers. If not, why not?) Extra credit: If you place a small mass a small distance z away from the center, use your Taylor limit for z << R above to write a simple ODE for the equation of motion. Solve it, and discuss the motion Back to Problem List 4 5 { GRAVITATION Last Updated: July 16, 2012 5.4 Gravitational force near a metal-cored planet surrounded by a gaseous cloud Given: Pollock { Spring 2011 Jupiter is composed of a dense spherical core (of liquid metallic hydrogen!) of radius Rc. It is sur- rounded by a spherical cloud of gaseous hydrogen of radius Rg, where Rg > Rc. Let’s assume that the core is of uniform density c and the gaseous cloud is also of uniform density g. What is the gravitational force on an object of mass m that is located at a radius r from the center of Jupiter? Note that you must consider the cases where the object is inside the core, within the gas layer, and outside of the planet. Back to Problem List 5 5 { GRAVITATION Last Updated: July 16, 2012 5.5 Sphere with linearly increasing mass density Given: Pollock { Spring 2011 A planet of mass M and radius R has a nonuniform density that varies with r, the distance from the center according to  = Ar for 0  r  R. (a) What is the constant A in terms of M and R? Does this density pro le strike you as physically plausible, or is just designed as a mathematical exercise? (Brie y, explain) (b) Determine the gravitational force on a satellite of mass m orbiting this planet. In words, please outline the method you plan to use for your solution. (Use the easiest method you can come up with!) In your calculation, you will need to argue that the magnitude of ~g(r; ; ) depends only on r. Be very explicit about this – how do you know that it doesn’t, in fact, depend on  or ? (c) Determine the gravitational force felt by a rock of mass m inside the planet, located at radius r < R. (If the method you use is di erent than in part b, explain why you switched. If not, just proceed!) Explicitly check your result for this part by considering the limits r ! 0 and r ! R. Back to Problem List 6 5 { GRAVITATION Last Updated: July 16, 2012 5.6 Jumping o Vesta Given: Pollock { Spring 2011 You are stranded on the surface of the asteroid Vesta. If the mass of the asteroid is M and its radius is R, how fast would you have to jump o its surface to be able to escape from its gravitational eld? (Your estimate should be based on parameters that characterize the asteroid, not parameters that describe your jumping ability.) Given your formula, look up the approximate mass and radius of the asteroid Vesta 3 and determine a numerical value of the escape velocity. Could you escape in this way? (Brie y, explain) If so, roughly how big in radius is the maximum the asteroid could be, for you to still escape this way? If not, estimate how much smaller an asteroid you would need, to escape from it in this way? Figure 1: Back to Problem List 7 5 { GRAVITATION Last Updated: July 16, 2012 5.7 Gravitational force between two massive rods Given: Pollock { Spring 2011 Consider two identical uniform rods of length L and mass m lying along the same line and having their closest points separated by a distance d as shown in the gure (a) Calculate the mutual force between these rods, both its direction and magnitude. (b) Now do several checks. First, make sure the units worked out (!) The, nd the magnitude of the force in the limit L ! 0. What do you expect? Brie y, discuss. Lastly, nd the magnitude of the force in the limit d ! 1 ? Again, is it what you expect? Brie y, discuss. Figure 2: Given: Pollock { Spring 2012 Determining the gravitational force between two rods: (a) Consider a thin, uniform rod of mass m and length L (and negligible other dimensions) lying on the x axis (from x=-L to 0), as shown in g 1a. Derive a formula for the gravitational eld \g" at any arbitrary point x to the right of the origin (but still on the x-axis!) due to this rod. (b) Now suppose a second rod of length L and mass m sits on the x axis as shown in g 1b, with the left edge a distance \d" away. Calculate the mutual gravitational force between these rods. (c) Let's do some checks! Show that the units work out in parts a and b. Find the magnitude of the force in part a, in the limit x >> L: What do you expect? Brie y, discuss! Finally, verify that your answer to part b gives what you expect in the limit d >> L. ( Hint: This is a bit harder! You need to consistently expand everything to second order, not just rst, because of some interesting cancellations) Fig 1a Fig 1b L m +x x=0 L x=0 x=d m Fig 1a Fig 1b L m +x x=0 L +x x=0 x=d L m m Back to Problem List 8 5 { GRAVITATION Last Updated: July 16, 2012 5.8 Potential energy { Check your answer! Given: Pollock { Spring 2011 On the last exam, we had a problem with a at ring, uniform mass per unit area of , inner radius of R, outer radius of 2R. A satellite (mass m) sat a distance z above the center of the ring. We asked for the gravitational potential energy, and the answer was U(z) = ?2Gm( p 4R2 + z2 ? p R2 + z2) (1) (a) If you are far from the disk (on the z axis), what do you expect for the formula for U(z)? (Don’t say \0″ – as usual, we want the functional form of U(z) as you move far away. Also, explicitly state what we mean by \far away”. (Please don’t compare something with units to something without units!) (b) Show explicitly that the formula above does indeed give precisely the functional dependence you expect. Back to Problem List 9 5 { GRAVITATION Last Updated: July 16, 2012 5.9 Ways of solving gravitational problems Given: Pollock { Spring 2011, Spring 2012 Infinite cylinder ρ=cr x z (a) Half-infinite line mass, uniform linear mass density, λ x (b) R z  P Figure 3: (a) An in nite cylinder of radius R centered on the z-axis, with non-uniform volume mass density  = cr, where r is the radius in cylindrical coordinates. (b) A half-in nite line of mass on the x-axis extending from x = 0 to x = +1, with uniform linear mass density . There are two general methods we use to solve gravitational problems (i.e. nd ~g given some distribution of mass). (a) Describe these two methods. We claim one of these methods is easiest to solve for ~g of mass distribution (a) above, and the other method is easiest to solve for ~g of the mass distribution (b) above. Which method goes with which mass distribution? Please justify your answer. (b) Find ~g of the mass distribution (a) above for any arbitrary point outside the cylinder. (c) Find the x component of the gravitational acceleration, gx, generated by the mass distribution labeled (b) above, at a point P a given distance z up the positive z-axis (as shown). Back to Problem List 10 5 { GRAVITATION Last Updated: July 16, 2012 5.10 Rod with linearly increasing mass density Given: Pollock { Spring 2012 Consider a very (in nitesimally!) thin but massive rod, length L (total mass M), centered around the origin, sitting along the x-axis. (So the left end is at (-L/2, 0,0) and the right end is at (+L/2,0,0) Assume the mass density  (which has units of kg/m)is not uniform, but instead varies linearly with distance from the origin, (x) = cjxj. (a) What is that constant \c” in terms of M and L? What is the direction of the gravitational eld generated by this mass distribution at a point in space a distance z above the center of the rod, i.e. at (0; 0; z) Explain your reasoning for the direction carefully, try not to simply \wave your hands.” (The answer is extremely intuitive, but can you justify that it is correct?) (b) Compute the gravitational eld, ~g, at the point (0; 0; z) by directly integrating Newton’s law of gravity, summing over all in nitesimal \chunks” of mass along the rod. (c) Compute the gravitational potential at the point (0; 0; z) by directly integrating ?Gdm=r, sum- ming over all in nitesimal \chunks” dm along the rod. Then, take the z-component of the gradient of this potential to check that you agree with your result from the previous part. (d) In the limit of large z what do you expect for the functional form for gravitational potential? (Hint: Don’t just say it goes to zero! It’s a rod of mass M, when you’re far away what does it look like? How does it go to zero?) What does \large z” mean here? Use the binomial (or Taylor) expansion to verify that your formula does indeed give exactly what you expect. (Hint: you cannot Taylor expand in something BIG, you have to Taylor expand in something small.) (e) Can you use Gauss’ law to gure out the gravitational potential at the point (0; 0; z)? (If so, do it and check your previous answers. If not, why not?) Back to Problem List 11 5 { GRAVITATION Last Updated: July 16, 2012 5.11 Sphere with constant internal gravitational eld Given: Pollock { Spring 2012 (a) Imagine a planet of total mass M and radius R which has a nonuniform mass density that varies just with r, the distance from the center. For this (admittedly very unusual!) planet, suppose the gravitational eld strength inside the planet turns out to be independent of the radial distance within the sphere. Find the function describing the mass density  = (r) of this planet. (Your nal answer should be written in terms of the given constants.) (b) Now, determine the gravitational force on a satellite of mass m orbiting this planet at distance r > R. (Use the easiest method you can come up with!) Explain your work in words as well as formulas. For instance, in your calculation, you will need to argue that the magnitude of ~g(r; ; ) depends only on r. Be explicit about this – how do you know that it doesn’t, in fact, depend on  or ? (c) As a nal check, explicitly show that your solutions inside and outside the planet (parts a and b) are consistent when r = R. Please also comment on whether this density pro le strikes you as physically plausible, or is it just designed as a mathematical exercise? Defend your reasoning. Back to Problem List 12 5 { GRAVITATION Last Updated: July 16, 2012 5.12 Throwing a rock o the moon Given: Pollock { Spring 2012 Assuming that asteroids have roughly the same mass density as the moon, make an estimate of the largest asteroid that an astronaut could be standing on, and still have a chance of throwing a small object (with their arms, no machinery!) so that it completely escapes the asteroid’s gravitational eld. (This minimum speed is called \escape velocity”) Is the size you computed typical for asteroids in our solar system? Back to Problem List 13