## What is the prime purpose of selecting a composite material over material from the other family groups? MODULE 3 – STRUCTURE OF SOLID MATERIALS The ability of a material to exist in different space lattices is called a. Allotropic b. Crystalline c. Solvent d. Amorphous Amorphous metals develop their microstructure as a result of ___________. a. Dendrites b. Directional solidification c. Slip d. Extremely rapid cooling In an alloy, the material that dissolves the alloying element is the ___________. a. Solute b. Solvent c. Matrix d. Allotrope What is the coordination number (CN) for the fcc structure formed by ions of sodium and chlorine that is in the chemical compound NaCl (salt) ? a. 6 b. 8 c. 14 d. 16 What pressure is normally used in constructing a phase diagram? a. 100 psi b. Depends on material c. Ambient d. Normal atmospheric pressure What line on a binary diagram indicates the upper limit of the solid solution phase? a. Liquidus b. Eutectic c. Eutectoid d. Solidus What holds the atoms (ions) together in a compound such as NaCl are electrostatic forces between ___________. a. Atom and ion b. Covalent bonds c. Electrons and nuclei d. Neutrons Diffusion of atoms through a solid takes place by two main mechanisms. One is diffusion through vacancies in the atomic structure. Another method of diffusion is ___________. a. Cold b. APF c. Substitutional d. Interstitial Give a brief explanation of the Lever rule (P117) Grain boundaries ___________ movement of dislocations through a solid. a. Improve b. Inhibit c. Do not affect Iron can be alloyed with carbon because it is ___________. a. Crystalline b. Amorphous c. A mixture d. Allotropic Metals can be cooled only to crystalline solids. a. T (true) b. F (false) Sketch an fcc unit cell. Metals are classified as crystalline materials. Name one metal that is an amorphous solid and name at least one recent application in which its use is saving energy or providing greater strength and/or corrosion resistance. MODULE 4 – MECHANICAL PROPERTIES Give two examples of a mechanical property. a. Thermal resistance b. Wear resistance c. Hardness d. Strength Scissors used in the home cut material by concentrating forces that ultimately produce a certain type of stress within the material. Identify this stress. a. Bearing stress b. Shearing stress c. Compressive stress An aluminum rod 1 in. in diameter (E =10.4 x 106psi) experiences an elastic tensile strain of 0.0048 in./in. Calculate the stress in the rod. a. 49,920 ksi b. 49,920 psi c. 49,920 msi A 1-in.-diameter steel circular rod is subject to a tensile load that reduces its cross-sectional area to 0.64 in2. Express the rod’s ductility using a standard unit of measure. a. 18.5% b. 1.85% c. 18.5 d. (a) and (c) What term is used to describe the low-temperature creep of polymerics? a. Springback b. Creep rupture c. Cold flow d. Creep forming MODULE 7 – TESTING, FAILURE ANALYSIS, STANDARDS, & INSPECTION Factors of safety are defined either in terms of the ultimate strength of a material or its yield strength. In other words, by the use of a suitable factor, the ultimate or yield strength is reduced in size to what is known as the design stress or safe working stress. Which factor of safety would be more appropriate for a material that will be subjected to repetitious, suddenly applied loads? Product liability court cases have risen sharply in recent years because of poor procedures in selecting materials for particular applications. Assuming that a knowledge of a material’s properties is a valid step in the selection process, cite two examples where such lack of knowledge could or did lead to failure or unsatisfactory performance. Make a sketch and fully dimension an Izod impact test specimen. Which agency publishes the Annual Book of standard test methods used worldwide for evaluation of materials? a. NASA b. NIST c. ASTM d. SPE

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## Course: PHYS 5426 — Quantum Statistical Physics Assignment #1 Instructor: Gennady Y. Chitov Date Assigned: January 15, 2014 Due Date: January 29, 2014 Problem 1. Prove [a; f(a†)] = @f(a†) @a† (1) [a†; f(a)] = −@f(a) @a (2) for arbitrary function f of operator which admits a series expansion. The Bose creation/ annihilation operators satisfy the standard commutation relations [a; a†] ≡ aa† − a†a = 1 (3) Hint: From Eqs.(1,2) one can figure out the corresponding commutation relations for the powers of creation/annihilation operators and then prove them by the method of mathematical induction. Note that for an arbitrary operator Aˆ: @A^n @A^ = nAˆn−1. Problem 2. In the presence of a constant external force acting on a one-dimensional oscillating particle its Hamiltonian becomes that of the so-called displaced oscillator, and the Schr¨odinger equation ˆH (q) = E (q) of the problem (cf. lecture notes) can be written in terms of dimensionless variables as ( − 1 2 d2 d2 + 1 2 2 − √ 2 ) () = ” () ; (4) where q = √ ~ m! and E = ~!”. a). Write the Schr¨odinger equation (4) in terms of the creation/annihilation operators of the harmonic oscillator ( = 0) = √1 2 (a + a†) (5) d d = √1 2 (a − a†) (6) 1 Via a linear transformation to the new creation/annihilation operators ˜a†; ˜a preserving the bosonic commutation relations for ˜a†; ˜a map the problem (4) of the displaced oscillator onto that of a simple harmonic oscillator with new operators (˜a†; ˜a). b). Find the spectrum (eigenvalues) ” (E) of the displaced oscillator. c). Write the normalized eigenstates |n⟩ of the displaced Hamiltonian (4) via a† and the vacuum state |Θ◦⟩ of the new operators, i.e. ˜a|Θ◦⟩ = 0 (7) d). As follows from the completeness of the oscillator’s eigenstates, the vacuum state of the displaced oscillator |Θ◦⟩ can be related to the simple oscillator’s vacuum |0⟩ (i.e., a|0⟩ = 0) as |Θ◦⟩ = Ω(a†)|0⟩ (8) Find (up to a normalization factor) the operator function Ω(a†) relating two vacua. Hint: in working out Eqs.(7,8), employ Eqs.(1,2). Problem 3. Prove from the standard commutation relations ([ai; a † j ]∓ = ij , etc) that ⟨0|aiaja † ka † l |0⟩ = jkil ± ikjl (9) the sign depending on the statistics. Also calculate the vacuum expectation value ⟨0|ahaiaja † ka † l a† m |0⟩. Problem 4. In the formalism of second quantization the two-particle interaction term of the Hamiltonian for spinless fermions is given by ˆ V = 1 2 ∫ ∫ dxdy ˆ †(x) ˆ †(y)V(x; y) ˆ (y) ˆ (x) (10) For the short-ranged interaction V(x; y) = V(|x−y|) ≡ V(r) = e2 exp(−r)=r find ˆ V in the momentum representation. The field operators and the creation/annihilation operators in the momentum representation are related in the usual way, i.e., ˆ †(x) = ∫ dp (2)3 a†(p)e−ipx (11) Note that the limit → 0 recovers the Coulomb (long-ranged) interaction V(r) = e2=r. What is the Fourier transform V(q) of the Coulomb interaction? 2 Problem 5. The matrix elements of a two-particle interaction from the previous problem can be written as ⟨k3k4|V|k1k2⟩ = (2)3(k1 + k2 − k3 − k4)V(q) (12) where q ≡ k3−k1 is the momentum transfer. Show that the diagonal part of the interaction operator ˆ V found on the previous problem in the k-representation, arises from momentum transfers q = 0 and q = k2−k1. Write down the two interaction terms and identify them as direct (q = 0) and exchange (q = k2 − k1) interactions. Draw the corresponding Feynman diagrams. Problem 6. Find the first correction to the temperature dependence of the chemical potential of the degenerate ideal electron gas, assuming constant particle concentration ⟨N⟩=V . Express the result in terms of T and the zero-temperature chemical potential ◦. For the calculations the following formula (we set kB = 1) can be used: I ≡ ∫ ∞ 0 f(“)d” e(“−)=T + 1 = ∫ 0 f(“)d” + 2 6 T2f′() + O(T4) (13) 3

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## Quiz Page 1 of 2 Note: It is recommended that you save your response as you complete each question. ________________________________________ Question 1 (1 point) Which of the following can cause cervicitis? Question 1 options: Candida Sexually transmitted infections Irritation from a contraceptive All of these choices are correct Question 2 (1 point) There is every indication that cervical cancer may take _____ or more years to develop. Question 2 options: 5 15 2 10 Question 3 (1 point) Cervical cancer is found almost exclusively in women who have been Question 3 options: sexually active underweight celibate overweight Question 4 (1 point) The best predictor for survival of ovarian cancer is Question 4 options: the sexual history of the patient how far the tumor has spread the amount of diagnostic measures taken the attitude (positive or negative) of the patient Question 5 (1 point) The current recommendation for most women, after becoming sexually active or starting at age 21, is to have a Pap smear done Question 5 options: once every 3 years once every year once every 5 years once every 6 months Page 1 of 2 ________________________________________ Quiz Page 2 of 2 Note: It is recommended that you save your response as you complete each question. Question 6 (1 point) Which of the following is not a fibroid classification? Question 6 options: Submucous Subserous Extramural Intramural Question 7 (1 point) Statistics indicate that _____ of breast cancers are diagnosed when women are between 45 and 64 years of age. Question 7 options: 47% 14% 22% 35% Question 8 (1 point) Ovarian cancers are classified according to their: Question 8 options: Cellular origin Symptoms Genetic predispositions All of these choices are correct Question 9 (1 point) The primary initial symptom of endometrial cancer is Question 9 options: odiferous vaginal discharge abnormal and painless vaginal bleeding painful, often incapacitating, cramps involuntary uterine contractions Question 10 (1 point) Ovarian cancers are considered the worst of gynecological malignancies because Question 10 options: they sometimes develop slowly they are often symptomless until it is too late too little is known about this disease both A and B are correct choices Page 2 of 2 Quiz 8 Quiz Page 2 of 2 Note: It is recommended that you save your response as you complete each question. Question 6 (1 point) The best predictor for survival of ovarian cancer is Question 6 options: the sexual history of the patient how far the tumor has spread the attitude (positive or negative) of the patient the amount of diagnostic measures taken Question 7 (1 point) Ovarian cancers are classified according to their: Question 7 options: Genetic predispositions Symptoms Cellular origin All of these choices are correct Question 8 (1 point) The primary initial symptom of endometrial cancer is Question 8 options: involuntary uterine contractions painful, often incapacitating, cramps abnormal and painless vaginal bleeding odiferous vaginal discharge Question 9 (1 point) Cervical cancer is found almost exclusively in women who have been Question 9 options: sexually active underweight celibate overweight Question 10 (1 point) Several screening techniques for early detection of ovarian cancer have been developed. As of yet _____ have proven effective. Question 10 options: 50% All None 25% Page 2 of 2 ________________________________________ Quiz Page 1 of 2 Note: It is recommended that you save your response as you complete each question. ________________________________________ Question 1 (1 point) The unsubstantiated idea that the uterus was damaged by sports and emotions remained common into the: Question 1 options: 1890s 1950s 1920s 1970s Question 2 (1 point) Which of the following can cause cervicitis? Question 2 options: Candida Sexually transmitted infections Irritation from a contraceptive All of these choices are correct Question 3 (1 point) There is every indication that cervical cancer may take _____ or more years to develop. Question 3 options: 10 5 2 15 Question 4 (1 point) Which of the following is not a fibroid classification? Question 4 options: Intramural Subserous Extramural Submucous Question 5 (1 point) Ovarian cancers are considered the worst of gynecological malignancies because Question 5 options: they sometimes develop slowly they are often symptomless until it is too late too little is known about this disease both A and B are correct choices Page 1 of 2 ________________________________________

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## Day 1 Homework Cover Sheet Name:_________________________________________________ Homework to do 1. Read Pages from Module 0 (pages 1-17), and Module 1 page 18. Or watch the videos listed below. Introduction To Authors (3 min) http://www.youtube.com/watch?v=oShZs_1U0Xk Introduction to Content ( 3min) http://www.youtube.com/watch?v=SiXM29eUw2k Introduction to the class and study skills (11 min) http://www.youtube.com/watch?v=th4cI8ugE-I Introduction to the class and study skills ( 8 min) http://www.youtube.com/watch?v=I5OktRxH79c Introduction to the class and study skills (10 min) http://www.youtube.com/watch?v=6WXLIf0FVIc 2. Attempt workbook pages 1-2. Summary of the lectures you watched. List any parts of the video lecture (if there are any) that were unclear or you had trouble understanding. Please be specific and do not just say “All of it”. Questions you had difficulty with or felt stuck on-

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## English 102 Assignment #8 Reflection 1: Reflecting on Researching & RQ One of our 102 GOALS says: Present compelling REFLECTIVE WRITING that accounts for and evaluates… • the evolution of your controlling purpose, through successive revisions, in relation to the project’s audience(s), stakeholders, and your own interests. • your composing and design strategies, developed through successive revisions, given your rhetorical situation. • how and why sources were chosen and used in the project. • your project in relation to your understanding of academic research and writing. Instead of one final reflective essay, we will do three shorter ones (a 3 part reflective). For this first reflective essay, reflect on what you have done in this course so far and how that has effected your thinking about academic research writing. Talk about your thinking about research and the process of researching. What is your own rhetorical situation? Then talk about the research you have done so far. What did you do and what was your thinking process while you were doing it. What sources did you choose and why? (What did you not choose, and why?) What was the rhetorical situation of that source? How do you intend to use it in your paper? How will it be useful? How did it effect your thinking on your topic/issue? Did any of our class readings, activities or discussion effect how you did research and/or your thinking about the research process? Next, talk about your topic/issue. What interested you about it, why? How did you formulate your research question? What makes a good research question? Why? Did any of our class readings, activities or discussion help you think about your research question? How will your research question help you research and write a research paper with critical inquiry? This should be at least two pages, typed MLA format. Bring it to our next class.

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## Matlab project Note: Your final project must be uniquely different from anyone else’s including different from the example I posted!! You are NOT allowed to work together because this is your individual final project!! Anyone caught working together or with similar data/answers will get an automatic zero and will be reported to the Dean’s Office!! REQUIREMENTS %%0. Make a main m-file that you use to run and call your function file. Give it a unique name. Make sure and include your name, your section, and date at the top of the m-file. Suppress any extraneous info; only output what is useful and what follows the intent of your program. (8 points) %%1. Create and use at least one anonymous function somewhere in your program. (5 points) %%2. Make a useful function m-file. That is, create and use at least one user-defined function Use comments immediately below the function definition line that describe what the function does and its inputs and outputs. (10 points) %%3. Utilize proper coding and documentation practices. Comment throughout both the main m-file and the function m-file. Create at least one section (cells). (12 points) %%4. Create and use either one subfunction or one nested function within your function mfile, (10 points) %%5. Use some type of numerical approximation technique like Runge Kutta, Euler’s method, Midpoint Rule, some type of numeric series, etc., 10 pts %%6. Create and use at least one loop (for/while/midpoint), 10 pts %%7. Create and use at least one conditional statement, 10 pts %%8. Create at least one plot, including a title and axes labels at a minimum, 10pts %%9. Output an organized display of your values to a text file that can be opened outside of MATLAB. Include headings so that the display makes sense. 10pts Note: Project need not be fancy or overcomplicated. You want to make sure it runs, meets all the listed requirements, is well-commented and is YOUR OWN WORK !! DELIVERABLES:!! %%10. Submit the following files onto blackboard (ZIP them!): 1. A flowchart or pseudocode of your program plan, 5pts 2. Your main project m-file, 0 credit if not included! 3. Your function m-file, -50% if not included!

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## Assignment 8 Due: 11:59pm on Friday, April 4, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Conceptual Question 10.3 Part A If a particle’s speed increases by a factor of 5, by what factor does its kinetic energy change? ANSWER: Correct Conceptual Question 10.11 A spring is compressed 1.5 . Part A How far must you compress a spring with twice the spring constant to store the same amount of energy? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct = 25 K2 K1 cm x = 1.1 cm Problem 10.2 The lowest point in Death Valley is below sea level. The summit of nearby Mt. Whitney has an elevation of 4420 . Part A What is the change in potential energy of an energetic 80 hiker who makes it from the floor of Death Valley to the top of Mt.Whitney? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Problem 10.3 Part A At what speed does a 1800 compact car have the same kinetic energy as a 1.80×104 truck going 21.0 ? Express your answer with the appropriate units. ANSWER: Correct Problem 10.5 A boy reaches out of a window and tosses a ball straight up with a speed of 13 . The ball is 21 above the ground as he releases it. 85m m kg U = 3.5×106 J kg kg km/hr vc = 66.4 km hr m/s m Part A Use energy to find the ball’s maximum height above the ground. Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Part B Use energy to find the ball’s speed as it passes the window on its way down. Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Part C Use energy to find the speed of impact on the ground. Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Hmax = 30 m v = 13 ms v = 24 ms Problem 10.8 A 59.0 skateboarder wants to just make it to the upper edge of a “quarter pipe,” a track that is one-quarter of a circle with a radius of 2.30 . Part A What speed does he need at the bottom? Express your answer with the appropriate units. ANSWER: Correct Problem 10.12 A 1500 car traveling at 12 suddenly runs out of gas while approaching the valley shown in the figure. The alert driver immediately puts the car in neutral so that it will roll. Part A kg m 6.71 ms kg m/s What will be the car’s speed as it coasts into the gas station on the other side of the valley? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Ups and Downs Learning Goal: To apply the law of conservation of energy to an object launched upward in the gravitational field of the earth. In the absence of nonconservative forces such as friction and air resistance, the total mechanical energy in a closed system is conserved. This is one particular case of the law of conservation of energy. In this problem, you will apply the law of conservation of energy to different objects launched from the earth. The energy transformations that take place involve the object’s kinetic energy and its gravitational potential energy . The law of conservation of energy for such cases implies that the sum of the object’s kinetic energy and potential energy does not change with time. This idea can be expressed by the equation , where “i” denotes the “initial” moment and “f” denotes the “final” moment. Since any two moments will work, the choice of the moments to consider is, technically, up to you. That choice, though, is usually suggested by the question posed in the problem. First, let us consider an object launched vertically upward with an initial speed . Neglect air resistance. Part A As the projectile goes upward, what energy changes take place? ANSWER: v = 6.8 ms K = (1/2)mv2 U = mgh Ki + Ui = Kf + Uf v Correct Part B At the top point of the flight, what can be said about the projectile’s kinetic and potential energy? ANSWER: Correct Strictly speaking, it is not the ball that possesses potential energy; rather, it is the system “Earth-ball.” Although we will often talk about “the gravitational potential energy of an elevated object,” it is useful to keep in mind that the energy, in fact, is associated with the interactions between the earth and the elevated object. Part C The potential energy of the object at the moment of launch __________. ANSWER: Both kinetic and potential energy decrease. Both kinetic and potential energy increase. Kinetic energy decreases; potential energy increases. Kinetic energy increases; potential energy decreases. Both kinetic and potential energy are at their maximum values. Both kinetic and potential energy are at their minimum values. Kinetic energy is at a maximum; potential energy is at a minimum. Kinetic energy is at a minimum; potential energy is at a maximum. Correct Usually, the zero level is chosen so as to make the relevant calculations simpler. In this case, it makes good sense to assume that at the ground level–but this is not, by any means, the only choice! Part D Using conservation of energy, find the maximum height to which the object will rise. Express your answer in terms of and the magnitude of the acceleration of gravity . ANSWER: Correct You may remember this result from kinematics. It is comforting to know that our new approach yields the same answer. Part E At what height above the ground does the projectile have a speed of ? Express your answer in terms of and the magnitude of the acceleration of gravity . ANSWER: is negative is positive is zero depends on the choice of the “zero level” of potential energy U = 0 hmax v g hmax = v2 2g h 0.5v v g h = 3 v2 8g Correct Part F What is the speed of the object at the height of ? Express your answer in terms of and . Use three significant figures in the numeric coefficient. Hint 1. How to approach the problem You are being asked for the speed at half of the maximum height. You know that at the initial height ( ), the speed is . All of the energy is kinetic energy, and so, the total energy is . At the maximum height, all of the energy is potential energy. Since the gravitational potential energy is proportional to , half of the initial kinetic energy must have been converted to potential energy when the projectile is at . Thus, the kinetic energy must be half of its original value (i.e., when ). You need to determine the speed, as a multiple of , that corresponds to such a kinetic energy. ANSWER: Correct Let us now consider objects launched at an angle. For such situations, using conservation of energy leads to a quicker solution than can be produced by kinematics. Part G A ball is launched as a projectile with initial speed at an angle above the horizontal. Using conservation of energy, find the maximum height of the ball’s flight. Express your answer in terms of , , and . Hint 1. Find the final kinetic energy Find the final kinetic energy of the ball. Here, the best choice of “final” moment is the point at which the ball reaches its maximum height, since this is the point we are interested in. u (1/2)hmax v g h = 0 v (1/2)mv2 h (1/2)hmax (1/4)mv2 h = (1/2)hmax v u = 0.707v v hmax v g Kf Express your answer in terms of , , and . Hint 1. Find the speed at the maximum height The speed of the ball at the maximum height is __________. ANSWER: ANSWER: ANSWER: Correct Part H A ball is launched with initial speed from ground level up a frictionless slope. The slope makes an angle with the horizontal. Using conservation of energy, find the maximum vertical height to which the ball will climb. Express your answer in terms of , , and . You may or may not use all of these quantities. v m 0 v v cos v sin v tan Kf = 0.5m(vcos())2 hmax = (vsin())2 2g v hmax v g ANSWER: Correct Interestingly, the answer does not depend on . The difference between this situation and the projectile case is that the ball moving up a slope has no kinetic energy at the top of its trajectory whereas the projectile launched at an angle does. Part I A ball is launched with initial speed from the ground level up a frictionless hill. The hill becomes steeper as the ball slides up; however, the ball remains in contact with the hill at all times. Using conservation of energy, find the maximum vertical height to which the ball will climb. Express your answer in terms of and . ANSWER: Correct The profile of the hill does not matter; the equation would have the same terms regardless of the steepness of the hill. Problem 10.14 A 12- -long spring is attached to the ceiling. When a 2.2 mass is hung from it, the spring stretches to a length of 17 . Part A What is the spring constant ? Express your answer to two significant figures and include the appropriate units. hmax = v2 2g v hmax v g hmax = v2 2g Ki + Ui = Kf + Uf cm kg cm k ANSWER: Correct Part B How long is the spring when a 3.0 mass is suspended from it? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Enhanced EOC: Problem 10.17 A 6.2 mass hanging from a spring scale is slowly lowered onto a vertical spring, as shown in . You may want to review ( pages 255 – 257) . For help with math skills, you may want to review: Solving Algebraic Equations = 430 k Nm kg y = 19 cm kg Part A What does the spring scale read just before the mass touches the lower spring? Express your answer to two significant figures and include the appropriate units. Hint 1. How to approach the problem Draw a picture showing the forces acting on the mass before it touches the scale. What is the net force on the mass? What is the force on the mass due to gravity? What is the force on the mass due to the scale? ANSWER: Correct Part B The scale reads 22 when the lower spring has been compressed by 2.7 . What is the value of the spring constant for the lower spring? Express your answer to two significant figures and include the appropriate units. Hint 1. How to approach the problem Draw a picture showing the forces acting on the mass. What is the net force on the mass? What is the force on the mass due to gravity? What is the force on the mass due to the scale? Use these to determine the force on the mass by the spring, taking note of the directions from your picture. How is the spring constant related to the force by the spring and the compression of the spring? Check your units. ANSWER: F = 61 N N cm k = 1400 k Nm Correct Part C At what compression length will the scale read zero? Express your answer to two significant figures and include the appropriate units. Hint 1. How to approach the problem Draw a picture showing the forces on the mass. When the scale reads zero, what is the force on the mass due to the scale? What is the gravitational force on the mass? What is the force on the mass by the spring? How is the compression length related to the force by the spring and the spring constant? Check your units. ANSWER: Correct Problem 10.18 Part A How far must you stretch a spring with = 800 to store 180 of energy? Express your answer to two significant figures and include the appropriate units. ANSWER: y = 4.2 cm k N/m J Correct Problem 10.22 A 15 runaway grocery cart runs into a spring with spring constant 230 and compresses it by 57 . Part A What was the speed of the cart just before it hit the spring? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Spring Gun A spring-loaded toy gun is used to shoot a ball straight up in the air. The ball reaches a maximum height , measured from the equilibrium position of the spring. s = 0.67 m kg N/m cm v = 2.2 ms H Part A The same ball is shot straight up a second time from the same gun, but this time the spring is compressed only half as far before firing. How far up does the ball go this time? Neglect friction. Assume that the spring is ideal and that the distance by which the spring is compressed is negligible compared to . Hint 1. Potential energy of the spring The potential energy of a spring is proportional to the square of the distance the spring is compressed. The spring was compressed half the distance, so the mass, when launched, has one quarter of the energy as in the first trial. Hint 2. Potential energy of the ball At the highest point in the ball’s trajectory, all of the spring’s potential energy has been converted into gravitational potential energy of the ball. ANSWER: Correct A Bullet Is Fired into a Wooden Block A bullet of mass is fired horizontally with speed at a wooden block of mass resting on a frictionless table. The bullet hits the block and becomes completely embedded within it. After the bullet has come to rest within the block, the block, with the bullet in it, is traveling at speed . H height = H 4 mb vi mw vf Part A Which of the following best describes this collision? Hint 1. Types of collisions An inelastic collision is a collision in which kinetic energy is not conserved. In a partially inelastic collision, kinetic energy is lost, but the objects colliding do not stick together. From this information, you can infer what completely inelastic and elastic collisions are. ANSWER: Correct Part B Which of the following quantities, if any, are conserved during this collision? Hint 1. When is kinetic energy conserved? Kinetic energy is conserved only in perfectly elastic collisions. ANSWER: perfectly elastic partially inelastic perfectly inelastic Correct Part C What is the speed of the block/bullet system after the collision? Express your answer in terms of , , and . Hint 1. Find the momentum after the collision What is the total momentum of the block/bullet system after the collision? Express your answer in terms of and other given quantities. ANSWER: Hint 2. Use conservation of momentum The momentum of the block/bullet system is conserved. Therefore, the momentum before the collision is the same as the momentum after the collision. Find a second expression for , this time expressed as the total momentum of the system before the collision. Express your answer in terms of and other given quantities. ANSWER: kinetic energy only momentum only kinetic energy and momentum neither momentum nor kinetic energy vi mw mb ptotal vf ptotal = (mw + mb)vf ptotal vi ptotal = mbvi ANSWER: Correct Problem 10.31 Ball 1, with a mass of 150 and traveling at 15.0 , collides head on with ball 2, which has a mass of 340 and is initially at rest. Part A What are the final velocities of each ball if the collision is perfectly elastic? Express your answer with the appropriate units. ANSWER: Correct Part B Express your answer with the appropriate units. ANSWER: Correct Part C vf = mb vi mb+mw g m/s g (vfx) = -5.82 1 ms (vfx) = 9.18 2 ms What are the final velocities of each ball if the collision is perfectly inelastic? Express your answer with the appropriate units. ANSWER: Correct Part D Express your answer with the appropriate units. ANSWER: Correct Enhanced EOC: Problem 10.43 A package of mass is released from rest at a warehouse loading dock and slides down the = 2.2 – high, frictionless chute to a waiting truck. Unfortunately, the truck driver went on a break without having removed the previous package, of mass , from the bottom of the chute. You may want to review ( pages 265 – 269) . For help with math skills, you may want to review: Solving Algebraic Equations (vfx) = 4.59 1 ms (vfx) = 4.59 2 ms m h m 2m Part A Suppose the packages stick together. What is their common speed after the collision? Express your answer to two significant figures and include the appropriate units. Hint 1. How to approach the problem There are two parts to this problem: the block sliding down the frictionless incline and the collision. What conservation laws are valid in each part? In terms of , what are the kinetic and potential energies of the block at the top of the incline? What is the potential energy of the same block at the bottom just before the collision? What are the kinetic energy and velocity of block just before the collision? What is conserved during the collision? What is the total momentum of the two blocks before the collision? What is the momentum of the two blocks stuck together after the collision? What is the velocity of the two blocks after the collision? ANSWER: Correct Part B Suppose the collision between the packages is perfectly elastic. To what height does the package of mass rebound? Express your answer to two significant figures and include the appropriate units. Hint 1. How to approach the problem There are three parts to this problem: the block sliding down the incline, the collision, and mass going back up the incline. What conservation laws are valid in each part? m m v = 2.2 ms m m What is an elastic collision? For an elastic collision, how are the initial and final velocities related when one of the masses is initially at rest? Using the velocity of just before the collision from Part A, what is the velocity of just after the collision in this case? What are the kinetic and potential energies of mass just after the collision? What is the kinetic energy of mass at its maximum rebound height? Using conservation of energy, what is the potential energy of mass at its maximum height? What is the maximum height? ANSWER: Correct Problem 10.35 A cannon tilted up at a 35.0 angle fires a cannon ball at 79.0 from atop a 21.0 -high fortress wall. Part A What is the ball’s impact speed on the ground below? Express your answer with the appropriate units. ANSWER: Correct Problem 10.45 A 1000 safe is 2.5 above a heavy-duty spring when the rope holding the safe breaks. The safe hits the spring and compresses it 48 . m m m m m h = 24 cm $ m/s m vf = 81.6 ms kg m cm Part A What is the spring constant of the spring? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Problem 10.49 A 100 block on a frictionless table is firmly attached to one end of a spring with = 21 . The other end of the spring is anchored to the wall. A 30 ball is thrown horizontally toward the block with a speed of 6.0 . Part A If the collision is perfectly elastic, what is the ball’s speed immediately after the collision? Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Part B What is the maximum compression of the spring? Express your answer to two significant figures and include the appropriate units. ANSWER: = 2.5×105 k Nm g k N/m g m/s v = 3.2 ms Correct Part C Repeat part A for the case of a perfectly inelastic collision. Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Part D Repeat part B for the case of a perfectly inelastic collision. Express your answer to two significant figures and include the appropriate units. ANSWER: Correct Score Summary: Your score on this assignment is 99.4%. You received 120.28 out of a possible total of 121 points. x = 0.19 m v = 1.4 ms x = 0.11 m

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## Week 8 Lessons: Fertility, Pregnancy, Childbirth, Contraception, Abortion and Sexuality Across the Life Span. After reading chapters 11, 12 and 13, focus on information presented in Boxes, Tables and Figures. Select a topic or information presented in Boxes, Tables or Figures in each of the three chapters. Identify at least one important topic from each chapter, use page citations, and make specific references to one of the additional teaching aids related to EACH chapter, giving each chapter and related teaching aid its own paragraph. (3 pts) In your 4th paragraph, briefly discuss one single piece of information from the readings and related teaching aids, that stood out for you and why. (1 pt) Capture the essence of your posting in a fifth paragraph, using ten words or less. Be sure to read classmate postings so you do not repeat topical information in your own posting.

Chapter 11: Pregnancy is confirmed by Hormonal Tests: Page 320 … Read More...

## 1-In _____ auctions, there is one buyer who wants to buy a product. Suppliers submit bids, and the lowest bid wins. forward static reverse physical simple 2- Which of the following is NOT an effect that e-commerce has had on organizations? E-commerce enables smaller businesses to operate in areas dominated by larger companies. E-commerce increases the number of potential customers to whom the company can market its products. E-commerce is a costly medium for increasing market share. E-commerce removes many barriers for start-up businesses. E-commerce makes it easy to reach customers around the world. 3- The degree of digitization relates to all of the following except: the product or service sold the process by which the product is produced the delivery agent or intermediary the size of e-commerce transactions None of these 4- In _______ e-commerce, the sellers and buyers are organizations. government-to-citizen consumer-to-consumer business-to-business business-to-consumer consumer-to-business 5- BitTorrent uses a process called _____, which eliminates file-sharing bottlenecks by having everyone share little pieces of a file at the same time. leeching collaboration packet switching torrents swarming 6- eBay uses a _____ auction. forward static reverse physical simple 7- A(n) _____ is a network designed to serve the internal informational needs of a single organization. global network extranet internet intranet World Wide Web 8- _____ are internet access points that are located in public places, such as libraries and airports. Clients Servers Internet access computers Network computer Internet kiosks 9- Consider this domain name: www.business.gsu.edu. The “edu” is the _______. top-level domain URL website locator name of the computer address of the webmaster 10- Internet service providers connect to one another through _____. internet connection points common carrier connection points network access points network connection points an extranet

1-In _____ auctions, there is one buyer who wants to … Read More...