Read: http://xnet.kp.org/permanentejournal/winter03/leader.html This article talks about physicians as leaders. It is written by a physician for physicians, so it provides insight into how doctors think of themselves in leadership. How can you use this understanding of doctors and leadership in managing your own healthcare facility? After all, the organizational chart shows the board of directors and CEO at the top, but physicians are just as important in leading any hospital or clinic. How will you integrate physicians as leaders in your own organization?

Read: http://xnet.kp.org/permanentejournal/winter03/leader.html This article talks about physicians as leaders. It is written by a physician for physicians, so it provides insight into how doctors think of themselves in leadership. How can you use this understanding of doctors and leadership in managing your own healthcare facility? After all, the organizational chart shows the board of directors and CEO at the top, but physicians are just as important in leading any hospital or clinic. How will you integrate physicians as leaders in your own organization?

The physicians always take a lead in creating patient-cantered care. … Read More...
Identify legislative and regulative requirements relative to information security for a bank

Identify legislative and regulative requirements relative to information security for a bank

A number of federal laws directly control the collection and … Read More...
High-stakes testing has become common in the United States and in many other countries. Do you think this has improved education, and why or why not?

High-stakes testing has become common in the United States and in many other countries. Do you think this has improved education, and why or why not?

I don’t think, high-stakes testing is helping. This issue in … Read More...
Faculty of Science Technology and Engineering Department of Physics Senior Laboratory Current balance Objectives When a steady electric current flows perpendicularly across a uniform magnetic field it experiences a force. This experiment aims to investigate this effect, and to determine the direction of the force relative to the current and magnetic field. You will design and perform a series of experiments to show how the magnitude of the force depends upon the current and the length of the conductor that is in the field. Task You are provided with a current balance apparatus (Figure 1), power supply and a magnet. This current balance consists of five loops of conducting wire supported on a pivoted aluminium frame. Current may be made to flow in one or up to five of the loops at a time in either direction. If the end of the loop is situated in a perpendicular magnetic field, when the current is switched on, the magnetic force on the current will unbalance the apparatus. By moving the sliding weights to rebalance it, the magnitude of this magnetic force may be measured. A scale is etched on one arm of the balance, so that the distance moved by the slider can be measured. The circuitry of the balance cannot cope currents greater than 5 Amps, so please do not exceed this level of current. Figure 1: Schematic diagram of current balance apparatus and circuitry. Start by familiarising yourself with the apparatus. Use the two sliding weights to balance the apparatus, then apply a magnetic field to either end of the loop. Pass a current through just one of the conducting loops and observe the direction of the resulting magnetic force, relative to the direction of the current and the applied field. Change the magnitude and direction of the current, observe qualitatively the effect this has on the magnetic force. Having familiarised yourself with the apparatus, you should design and perform a series of quantitative experiments aiming to: (1) determine how the size of the magnetic force is dependant on the size of the current flowing in the conductor. (2) determine how the size of the force is dependant on the length of the conductor which is in the field. (3) measure the value (in Tesla) of the field of the magnet provided. For each of these, the balance should be set up with the magnet positioned at the end of the arm that has the distance scale, and orientated so that the magnetic force will be directed upwards when a current is passed through the conductor. The sliding weight on this arm should be positioned at the zero-mark. The weight on the opposite arm should be adjusted to balance the apparatus in the absence of a current. When a current is applied, you should re-balance the apparatus by moving the weight on the scaled arm outwards, while keeping the opposite weight fixed in position. The distance moved by the weight is directly proportional to the force applied by the magnetic field to the end of the balance. In your report, make sure you discuss why this is the case. Use the position of the sliding weight to quantify the magnetic force as a function of the current applied to the conductor, and of the number of conducting loops through which the current flows. For tasks (1) and (2) you can use the position of the sliding weight as a measure of the force. Look up the relationship that relates the force to the applied field, current and length of conductor in the field. Is this consistent with your data? To complete task (3) you need to determine the magnitude (in Newtons) of the magnetic force from the measurement of the position of the sliding weight. To do this, what other information do you need to know? When you have determined a value for the field, you can measure the field directly using the laboratory’s Gaussmeter for comparison.

Faculty of Science Technology and Engineering Department of Physics Senior Laboratory Current balance Objectives When a steady electric current flows perpendicularly across a uniform magnetic field it experiences a force. This experiment aims to investigate this effect, and to determine the direction of the force relative to the current and magnetic field. You will design and perform a series of experiments to show how the magnitude of the force depends upon the current and the length of the conductor that is in the field. Task You are provided with a current balance apparatus (Figure 1), power supply and a magnet. This current balance consists of five loops of conducting wire supported on a pivoted aluminium frame. Current may be made to flow in one or up to five of the loops at a time in either direction. If the end of the loop is situated in a perpendicular magnetic field, when the current is switched on, the magnetic force on the current will unbalance the apparatus. By moving the sliding weights to rebalance it, the magnitude of this magnetic force may be measured. A scale is etched on one arm of the balance, so that the distance moved by the slider can be measured. The circuitry of the balance cannot cope currents greater than 5 Amps, so please do not exceed this level of current. Figure 1: Schematic diagram of current balance apparatus and circuitry. Start by familiarising yourself with the apparatus. Use the two sliding weights to balance the apparatus, then apply a magnetic field to either end of the loop. Pass a current through just one of the conducting loops and observe the direction of the resulting magnetic force, relative to the direction of the current and the applied field. Change the magnitude and direction of the current, observe qualitatively the effect this has on the magnetic force. Having familiarised yourself with the apparatus, you should design and perform a series of quantitative experiments aiming to: (1) determine how the size of the magnetic force is dependant on the size of the current flowing in the conductor. (2) determine how the size of the force is dependant on the length of the conductor which is in the field. (3) measure the value (in Tesla) of the field of the magnet provided. For each of these, the balance should be set up with the magnet positioned at the end of the arm that has the distance scale, and orientated so that the magnetic force will be directed upwards when a current is passed through the conductor. The sliding weight on this arm should be positioned at the zero-mark. The weight on the opposite arm should be adjusted to balance the apparatus in the absence of a current. When a current is applied, you should re-balance the apparatus by moving the weight on the scaled arm outwards, while keeping the opposite weight fixed in position. The distance moved by the weight is directly proportional to the force applied by the magnetic field to the end of the balance. In your report, make sure you discuss why this is the case. Use the position of the sliding weight to quantify the magnetic force as a function of the current applied to the conductor, and of the number of conducting loops through which the current flows. For tasks (1) and (2) you can use the position of the sliding weight as a measure of the force. Look up the relationship that relates the force to the applied field, current and length of conductor in the field. Is this consistent with your data? To complete task (3) you need to determine the magnitude (in Newtons) of the magnetic force from the measurement of the position of the sliding weight. To do this, what other information do you need to know? When you have determined a value for the field, you can measure the field directly using the laboratory’s Gaussmeter for comparison.

Abstract   The present experiment aims to investigate the effect … Read More...
Faculty of Science Technology and Engineering Department of Physics Senior Laboratory Faraday rotation AIM To show that optical activity is induced in a certain type of glass when it is in a magnetic field. To investigate the degree of rotation of linearly polarised light as a function of the applied magnetic field and hence determine a parameter which is characteristic of each material and known as Verdet’s constant. BACKGROUND INFORMATION A brief description of the properties and production of polarised light is given in the section labelled: Notes on polarisation. This should be read before proceeding with this experiment. Additional details may be found in the references listed at the end of this experiment. Whereas some materials, such as quartz, are naturally optically active, optical activity can be induced in others by the application of a magnetic field. For such materials, the angle through which the plane of polarisation of a linearly polarised beam is rotated () depends on the thickness of the sample (L), the strength of the magnetic field (B) and on the properties of the particular material. The latter is described by means of a parameter introduced by Verdet, which is wavelength dependent. Thus:  = V B L Lamp Polariser Solenoid Polariser Glass rod A Solenoid power supply Viewing mirror EXPERIMENTAL PROCEDURE The experimental arrangement is shown in the diagram. Unpolarised white light is produced by a hot filament and viewed using a mirror. • The light from the globe passes through two polarisers as well as the specially doped glass rod. Select one of the colour filters provided and place in the light path. Each of these filters transmits a relatively narrow band of wavelengths centred around a dominant wavelength as listed in the table. Filter No. Dominant Wavelength 98 4350 Å 50 4500 75 4900 58 5300 72 B 6060 92 6700 With the power supply for the coil switched off, (do not simply turn the potentiometer to zero: this still allows some current to flow) adjust one of the polarisers until minimum light is transmitted to the mirror. Minimum transmission can be determined visually. • Decide which polariser you will work with and do not alter the other one during the measurements. • The magnetic field is generated by a current in a solenoid (coil) placed around the glass rod. As the current in the coil is increased, the magnitude of the magnetic field will increase as shown on the calibration curve below. The degree of optical activity will also increase, resulting in some angle of rotation of the plane of polarisation. Hence you will need to rotate your chosen polariser to regain a minimum setting. 0 1 2 3 4 5 0.00 0.02 0.04 0.06 0.08 I (amps) B (tesla) Magnetic field (B) produced by current (I) in solenoid • Record the rotation angle () for coil currents of 0,1,2,3,4 and 5 amps. Avoid having the current in the coil switched on except when measurements are actually being taken as it can easily overheat. If the coil becomes too hot to touch, switch it off and wait for it to cool before proceeding. • Plot  as a function of B and, given that the length of the glass rod is 30 cm, determine Verdet’s constant for this material at the wavelength () in use. • Repeat the experiment for each of the wavelengths available using the filter set provided. • Calculate the logarithm for each V and  and tabulate the results. By plotting log V against log , determine the relationship between V and . [Hint: m log(x) = log (xm) and log(xy) = log(x) + log(y)]. • Calculate the errors involved in your determination of V. The uncertainty in a value of B may be taken as the uncertainty in reading the scale of the calibration curve) • The magnetic field direction can be reversed by reversing the direction of current flow in the coil. Describe the effect of this reversal and provide an explanation. Reference Optics Hecht.

Faculty of Science Technology and Engineering Department of Physics Senior Laboratory Faraday rotation AIM To show that optical activity is induced in a certain type of glass when it is in a magnetic field. To investigate the degree of rotation of linearly polarised light as a function of the applied magnetic field and hence determine a parameter which is characteristic of each material and known as Verdet’s constant. BACKGROUND INFORMATION A brief description of the properties and production of polarised light is given in the section labelled: Notes on polarisation. This should be read before proceeding with this experiment. Additional details may be found in the references listed at the end of this experiment. Whereas some materials, such as quartz, are naturally optically active, optical activity can be induced in others by the application of a magnetic field. For such materials, the angle through which the plane of polarisation of a linearly polarised beam is rotated () depends on the thickness of the sample (L), the strength of the magnetic field (B) and on the properties of the particular material. The latter is described by means of a parameter introduced by Verdet, which is wavelength dependent. Thus:  = V B L Lamp Polariser Solenoid Polariser Glass rod A Solenoid power supply Viewing mirror EXPERIMENTAL PROCEDURE The experimental arrangement is shown in the diagram. Unpolarised white light is produced by a hot filament and viewed using a mirror. • The light from the globe passes through two polarisers as well as the specially doped glass rod. Select one of the colour filters provided and place in the light path. Each of these filters transmits a relatively narrow band of wavelengths centred around a dominant wavelength as listed in the table. Filter No. Dominant Wavelength 98 4350 Å 50 4500 75 4900 58 5300 72 B 6060 92 6700 With the power supply for the coil switched off, (do not simply turn the potentiometer to zero: this still allows some current to flow) adjust one of the polarisers until minimum light is transmitted to the mirror. Minimum transmission can be determined visually. • Decide which polariser you will work with and do not alter the other one during the measurements. • The magnetic field is generated by a current in a solenoid (coil) placed around the glass rod. As the current in the coil is increased, the magnitude of the magnetic field will increase as shown on the calibration curve below. The degree of optical activity will also increase, resulting in some angle of rotation of the plane of polarisation. Hence you will need to rotate your chosen polariser to regain a minimum setting. 0 1 2 3 4 5 0.00 0.02 0.04 0.06 0.08 I (amps) B (tesla) Magnetic field (B) produced by current (I) in solenoid • Record the rotation angle () for coil currents of 0,1,2,3,4 and 5 amps. Avoid having the current in the coil switched on except when measurements are actually being taken as it can easily overheat. If the coil becomes too hot to touch, switch it off and wait for it to cool before proceeding. • Plot  as a function of B and, given that the length of the glass rod is 30 cm, determine Verdet’s constant for this material at the wavelength () in use. • Repeat the experiment for each of the wavelengths available using the filter set provided. • Calculate the logarithm for each V and  and tabulate the results. By plotting log V against log , determine the relationship between V and . [Hint: m log(x) = log (xm) and log(xy) = log(x) + log(y)]. • Calculate the errors involved in your determination of V. The uncertainty in a value of B may be taken as the uncertainty in reading the scale of the calibration curve) • The magnetic field direction can be reversed by reversing the direction of current flow in the coil. Describe the effect of this reversal and provide an explanation. Reference Optics Hecht.

Top of Form Abstract.     Faraday Effect or Faraday … 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...
Define: 41 Things Philosophy is: 1. Ignorant 2. Selfish 3. Ironic 4. Plain 5. Misunderstood 6. A failure 7. Poor 8. Unscientific 9. Unteachable 10. Foolish 11. Abnormal 12. Divine trickery 13. Egalitarian 14. A divine calling 15. Laborious 16. Countercultural 17. Uncomfortable 18. Virtuous 19. Dangerous 20. Simplistic<br />21. Polemical 22. Therapeutic 23. “conformist” 24. Embarrassi ng 25. Invulnerable 26. Annoying 27. Pneumatic 28. Apolitic al 29. Docile/teachable 30. Messianic 31. Pious 32. Impract ical 33. Happy 34. Necessary 35. Death-defying 36. Fallible 37. Immortal 38. Confident 39. Painful 40. agnostic</br

Define: 41 Things Philosophy is: 1. Ignorant 2. Selfish 3. Ironic 4. Plain 5. Misunderstood 6. A failure 7. Poor 8. Unscientific 9. Unteachable 10. Foolish 11. Abnormal 12. Divine trickery 13. Egalitarian 14. A divine calling 15. Laborious 16. Countercultural 17. Uncomfortable 18. Virtuous 19. Dangerous 20. Simplistic
21. Polemical 22. Therapeutic 23. “conformist” 24. Embarrassi ng 25. Invulnerable 26. Annoying 27. Pneumatic 28. Apolitic al 29. Docile/teachable 30. Messianic 31. Pious 32. Impract ical 33. Happy 34. Necessary 35. Death-defying 36. Fallible 37. Immortal 38. Confident 39. Painful 40. agnostic

Ignorant- A person is said to be ignorant if he … Read More...
ABC Corporation’s HRD department has a business meeting with the strategic planning committee to discuss succession planning. You have been asked to come up with a small-group discussion or activity related to career development. The entire meeting will focus on this topic and will begin with a presentation by the HRD Director, followed by a panel discussion, followed by this activity.

ABC Corporation’s HRD department has a business meeting with the strategic planning committee to discuss succession planning. You have been asked to come up with a small-group discussion or activity related to career development. The entire meeting will focus on this topic and will begin with a presentation by the HRD Director, followed by a panel discussion, followed by this activity.

OCCUPATION DEVELOPMENT ACTION PLAN addresses our individual and occupation growth … Read More...
Chapter 15 Practice Problems (Practice – no credit) Due: 11:59pm on Friday, May 16, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Fluid Pressure in a U-Tube A U-tube is filled with water, and the two arms are capped. The tube is cylindrical, and the right arm has twice the radius of the left arm. The caps have negligible mass, are watertight, and can freely slide up and down the tube. Part A A one-inch depth of sand is poured onto the cap on each arm. After the caps have moved (if necessary) to reestablish equilibrium, is the right cap higher, lower, or the same height as the left cap? You did not open hints for this part. ANSWER: Part B This question will be shown after you complete previous question(s). Part C This question will be shown after you complete previous question(s). Part D This question will be shown after you complete previous question(s). Pressure in the Ocean The pressure at 10 below the surface of the ocean is about 2.00×105 . Part A higher lower the same height m Pa Which of the following statements is true? You did not open hints for this part. ANSWER: Part B Now consider the pressure 20 below the surface of the ocean. Which of the following statements is true? You did not open hints for this part. ANSWER: Relating Pressure and Height in a Container Learning Goal: To understand the derivation of the law relating height and pressure in a container. The weight of a column of seawater 1 in cross section and 10 high is about 2.00×105 . The weight of a column of seawater 1 in cross section and 10 high plus the weight of a column of air with the same cross section extending up to the top of the atmosphere is about 2.00×105 . The weight of 1 of seawater at 10 below the surface of the ocean is about 2.00×105 . The density of seawater is about 2.00×105 times the density of air at sea level. m2 m N m2 m N m3 m N m The pressure is twice that at a depth of 10 . The pressure is the same as that at a depth of 10 . The pressure is equal to that at a depth of 10 plus the weight per 1 cross sectional area of a column of seawater 10 high. The pressure is equal to the weight per 1 cross sectional area of a column of seawater 20 high. m m m m2 m m2 m In this problem, you will derive the law relating pressure to height in a container by analyzing a particular system. A container of uniform cross-sectional area is filled with liquid of uniform density . Consider a thin horizontal layer of liquid (thickness ) at a height as measured from the bottom of the container. Let the pressure exerted upward on the bottom of the layer be and the pressure exerted downward on the top be . Assume throughout the problem that the system is in equilibrium (the container has not been recently shaken or moved, etc.). Part A What is , the magnitude of the force exerted upward on the bottom of the liquid? You did not open hints for this part. ANSWER: Part B What is , the magnitude of the force exerted downward on the top of the liquid? A  dy y p p + dp Fup Fup = Fdown You did not open hints for this part. ANSWER: Part C What is the weight of the thin layer of liquid? Express your answer in terms of quantities given in the problem introduction and , the magnitude of the acceleration due to gravity. You did not open hints for this part. ANSWER: Part D Since the liquid is in equilibrium, the net force on the thin layer of liquid is zero. Complete the force equation for the sum of the vertical forces acting on the liquid layer described in the problem introduction. Express your answer in terms of quantities given in the problem introduction and taking upward forces to be positive. You did not open hints for this part. ANSWER: Fdown = wlayer g wlayer = 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). A Submerged Ball A ball of mass and volume is lowered on a string into a fluid of density . Assume that the object would sink to the bottom if it were not supported by the string. Part A  = = i Fy,i mb V f What is the tension in the string when the ball is fully submerged but not touching the bottom, as shown in the figure? Express your answer in terms of any or all of the given quantities and , the magnitude of the acceleration due to gravity. You did not open hints for this part. ANSWER: Archimedes’ Principle Learning Goal: To understand the applications of Archimedes’ principle. Archimedes’ principle is a powerful tool for solving many problems involving equilibrium in fluids. It states the following: When a body is partially or completely submerged in a fluid (either a liquid or a gas), the fluid exerts an upward force on the body equal to the weight of the fluid displaced by the body. As a result of the upward Archimedes force (often called the buoyant force), some objects may float in a fluid, and all of them appear to weigh less. This is the familiar phenomenon of buoyancy. Quantitatively, the buoyant force can be found as , where is the force, is the density of the fluid, is the magnitude of the acceleration due to gravity, and is the volume of the displaced fluid. In this problem, you will be asked several qualitative questions that should help you develop a feel for Archimedes’ principle. An object is placed in a fluid and then released. Assume that the object either floats to the surface (settling so that the object is partly above and partly below the fluid surface) or sinks to the bottom. (Note that for Parts A through D, you should assume that the object has settled in equilibrium.) Part A Consider the following statement: The magnitude of the buoyant force is equal to the weight of fluid displaced by the object. Under what circumstances is this statement true? T g T = Fbuoyant = fluidgV Fbuoyant fluid g V You did not open hints for this part. ANSWER: Part B Consider the following statement: The magnitude of the buoyant force is equal to the weight of the amount of fluid that has the same total volume as the object. Under what circumstances is this statement true? You did not open hints for this part. ANSWER: Part C Consider the following statement: The magnitude of the buoyant force equals the weight of the object. Under what circumstances is this statement true? for every object submerged partially or completely in a fluid only for an object that floats only for an object that sinks for no object submerged in a fluid for an object that is partially submerged in a fluid only for an object that floats for an object completely submerged in a fluid for no object partially or completely submerged in a fluid You did not open hints for this part. ANSWER: Part D Consider the following statement: The magnitude of the buoyant force is less than the weight of the object. Under what circumstances is this statement true? ANSWER: Now apply what you know to some more complicated situations. Part E An object is floating in equilibrium on the surface of a liquid. The object is then removed and placed in another container, filled with a denser liquid. What would you observe? You did not open hints for this part. ANSWER: for every object submerged partially or completely in a fluid for an object that floats only for an object that sinks for no object submerged in a fluid for every object submerged partially or completely in a fluid for an object that floats for an object that sinks for no object submerged in a fluid Part F An object is floating in equilibrium on the surface of a liquid. The object is then removed and placed in another container, filled with a less dense liquid. What would you observe? You did not open hints for this part. ANSWER: Part G Two objects, T and B, have identical size and shape and have uniform density. They are carefully placed in a container filled with a liquid. Both objects float in equilibrium. Less of object T is submerged than of object B, which floats, fully submerged, closer to the bottom of the container. Which of the following statements is true? ANSWER: The object would sink all the way to the bottom. The object would float submerged more deeply than in the first container. The object would float submerged less deeply than in the first container. More than one of these outcomes is possible. The object would sink all the way to the bottom. The object would float submerged more deeply than in the first container. The object would float submerged less deeply than in the first container. More than one of these outcomes is possible. Object T has a greater density than object B. Object B has a greater density than object T. Both objects have the same density. ± Buoyant Force Conceptual Question A rectangular wooden block of weight floats with exactly one-half of its volume below the waterline. Part A What is the buoyant force acting on the block? You did not open hints for this part. ANSWER: Part B W The buoyant force cannot be determined. 2W W 1 W 2 The density of water is 1.00 . What is the density of the block? You did not open hints for this part. ANSWER: Part C This question will be shown after you complete previous question(s). 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). g/cm3 2.00 between 1.00 and 2.00 1.00 between 0.50 and 1.00 0.50 The density cannot be determined. g/cm3 g/cm3 g/cm3 g/cm3 g/cm3 Flow Velocity of Blood Conceptual Question Arteriosclerotic plaques forming on the inner walls of arteries can decrease the effective cross-sectional area of an artery. Even small changes in the effective area of an artery can lead to very large changes in the blood pressure in the artery and possibly to the collapse of the blood vessel. Imagine a healthy artery, with blood flow velocity of and mass per unit volume of . The kinetic energy per unit volume of blood is given by Imagine that plaque has narrowed an artery to one-fifth of its normal cross-sectional area (an 80% blockage). Part A Compared to normal blood flow velocity, , what is the velocity of blood as it passes through this blockage? You did not open hints for this part. ANSWER: Part B This question will be shown after you complete previous question(s). Part C v0 = 0.14 m/s  = 1050 kg/m3 K0 =  . 1 2 v20 v0 80v0 20v0 5v0 v0/5 This question will be shown after you complete previous question(s). For parts D – F imagine that plaque has grown to a 90% blockage. 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). ± Playing with a Water Hose Two children, Ferdinand and Isabella, are playing with a water hose on a sunny summer day. Isabella is holding the hose in her hand 1.0 meters above the ground and is trying to spray Ferdinand, who is standing 10.0 meters away. Part A Will Isabella be able to spray Ferdinand if the water is flowing out of the hose at a constant speed of 3.5 meters per second? Assume that the hose is pointed parallel to the ground and take the magnitude of the acceleration due to gravity to be 9.81 meters per second, per second. You did not open hints for this part. v0 g ANSWER: Part B This question will be shown after you complete previous question(s). Tactics Box 15.2 Finding Whether an Object Floats or Sinks Learning Goal: To practice Tactics Box 15.2 Finding whether an object floats or sinks. If you hold an object underwater and then release it, it can float to the surface, sink, or remain “hanging” in the water, depending on whether the fluid density is larger than, smaller than, or equal to the object’s average density . These conditions are summarized in this Tactics Box. Yes No f avg TACTICS BOX 15.2 Finding whether an object floats or sinks Object sinks Object floats Object has neutral buoyancy An object sinks if it weighs more than the fluid it displaces, that is, if its average density is greater than the density of the fluid: . An object floats on the surface if it weighs less than the fluid it displaces, that is, if its average density is less than the density of the fluid: . An object hangs motionless in the fluid if it weighs exactly the same as the fluid it displaces. It has neutral buoyancy if its average density equals the density of the fluid: . Part A Ice at 0.0 has a density of 917 . A 3.00 ice cube is gently released inside a small container filled with oil and is observed to be neutrally buoyant. What is the density of the oil, ? Express your answer in kilograms per meter cubed to three significant figures. ANSWER: Part B Once the ice cube melts, what happens to the liquid water that it produces? You did not open hints for this part. ANSWER: avg > f avg < f avg = f 'C kg/m3 cm3 oil oil = kg/m3 Part C What happens if some ethyl alcohol of density 790 is poured into the container after the ice cube has melted? ANSWER: Score Summary: Your score on this assignment is 0%. You received 0 out of a possible total of 0 points. The liquid water sinks to the bottom of the container. The liquid water rises to the surface and floats on top of the oil. The liquid water is in static equilibrium at the location where the ice cube was originally placed. kg/m3 A layer of ethyl alcohol forms between the oil and the water. The layer of ethyl alcohol forms at the bottom of the container. The layer of ethyl alcohol forms on the surface.

Chapter 15 Practice Problems (Practice – no credit) Due: 11:59pm on Friday, May 16, 2014 You will receive no credit for items you complete after the assignment is due. Grading Policy Fluid Pressure in a U-Tube A U-tube is filled with water, and the two arms are capped. The tube is cylindrical, and the right arm has twice the radius of the left arm. The caps have negligible mass, are watertight, and can freely slide up and down the tube. Part A A one-inch depth of sand is poured onto the cap on each arm. After the caps have moved (if necessary) to reestablish equilibrium, is the right cap higher, lower, or the same height as the left cap? You did not open hints for this part. ANSWER: Part B This question will be shown after you complete previous question(s). Part C This question will be shown after you complete previous question(s). Part D This question will be shown after you complete previous question(s). Pressure in the Ocean The pressure at 10 below the surface of the ocean is about 2.00×105 . Part A higher lower the same height m Pa Which of the following statements is true? You did not open hints for this part. ANSWER: Part B Now consider the pressure 20 below the surface of the ocean. Which of the following statements is true? You did not open hints for this part. ANSWER: Relating Pressure and Height in a Container Learning Goal: To understand the derivation of the law relating height and pressure in a container. The weight of a column of seawater 1 in cross section and 10 high is about 2.00×105 . The weight of a column of seawater 1 in cross section and 10 high plus the weight of a column of air with the same cross section extending up to the top of the atmosphere is about 2.00×105 . The weight of 1 of seawater at 10 below the surface of the ocean is about 2.00×105 . The density of seawater is about 2.00×105 times the density of air at sea level. m2 m N m2 m N m3 m N m The pressure is twice that at a depth of 10 . The pressure is the same as that at a depth of 10 . The pressure is equal to that at a depth of 10 plus the weight per 1 cross sectional area of a column of seawater 10 high. The pressure is equal to the weight per 1 cross sectional area of a column of seawater 20 high. m m m m2 m m2 m In this problem, you will derive the law relating pressure to height in a container by analyzing a particular system. A container of uniform cross-sectional area is filled with liquid of uniform density . Consider a thin horizontal layer of liquid (thickness ) at a height as measured from the bottom of the container. Let the pressure exerted upward on the bottom of the layer be and the pressure exerted downward on the top be . Assume throughout the problem that the system is in equilibrium (the container has not been recently shaken or moved, etc.). Part A What is , the magnitude of the force exerted upward on the bottom of the liquid? You did not open hints for this part. ANSWER: Part B What is , the magnitude of the force exerted downward on the top of the liquid? A  dy y p p + dp Fup Fup = Fdown You did not open hints for this part. ANSWER: Part C What is the weight of the thin layer of liquid? Express your answer in terms of quantities given in the problem introduction and , the magnitude of the acceleration due to gravity. You did not open hints for this part. ANSWER: Part D Since the liquid is in equilibrium, the net force on the thin layer of liquid is zero. Complete the force equation for the sum of the vertical forces acting on the liquid layer described in the problem introduction. Express your answer in terms of quantities given in the problem introduction and taking upward forces to be positive. You did not open hints for this part. ANSWER: Fdown = wlayer g wlayer = 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). A Submerged Ball A ball of mass and volume is lowered on a string into a fluid of density . Assume that the object would sink to the bottom if it were not supported by the string. Part A  = = i Fy,i mb V f What is the tension in the string when the ball is fully submerged but not touching the bottom, as shown in the figure? Express your answer in terms of any or all of the given quantities and , the magnitude of the acceleration due to gravity. You did not open hints for this part. ANSWER: Archimedes’ Principle Learning Goal: To understand the applications of Archimedes’ principle. Archimedes’ principle is a powerful tool for solving many problems involving equilibrium in fluids. It states the following: When a body is partially or completely submerged in a fluid (either a liquid or a gas), the fluid exerts an upward force on the body equal to the weight of the fluid displaced by the body. As a result of the upward Archimedes force (often called the buoyant force), some objects may float in a fluid, and all of them appear to weigh less. This is the familiar phenomenon of buoyancy. Quantitatively, the buoyant force can be found as , where is the force, is the density of the fluid, is the magnitude of the acceleration due to gravity, and is the volume of the displaced fluid. In this problem, you will be asked several qualitative questions that should help you develop a feel for Archimedes’ principle. An object is placed in a fluid and then released. Assume that the object either floats to the surface (settling so that the object is partly above and partly below the fluid surface) or sinks to the bottom. (Note that for Parts A through D, you should assume that the object has settled in equilibrium.) Part A Consider the following statement: The magnitude of the buoyant force is equal to the weight of fluid displaced by the object. Under what circumstances is this statement true? T g T = Fbuoyant = fluidgV Fbuoyant fluid g V You did not open hints for this part. ANSWER: Part B Consider the following statement: The magnitude of the buoyant force is equal to the weight of the amount of fluid that has the same total volume as the object. Under what circumstances is this statement true? You did not open hints for this part. ANSWER: Part C Consider the following statement: The magnitude of the buoyant force equals the weight of the object. Under what circumstances is this statement true? for every object submerged partially or completely in a fluid only for an object that floats only for an object that sinks for no object submerged in a fluid for an object that is partially submerged in a fluid only for an object that floats for an object completely submerged in a fluid for no object partially or completely submerged in a fluid You did not open hints for this part. ANSWER: Part D Consider the following statement: The magnitude of the buoyant force is less than the weight of the object. Under what circumstances is this statement true? ANSWER: Now apply what you know to some more complicated situations. Part E An object is floating in equilibrium on the surface of a liquid. The object is then removed and placed in another container, filled with a denser liquid. What would you observe? You did not open hints for this part. ANSWER: for every object submerged partially or completely in a fluid for an object that floats only for an object that sinks for no object submerged in a fluid for every object submerged partially or completely in a fluid for an object that floats for an object that sinks for no object submerged in a fluid Part F An object is floating in equilibrium on the surface of a liquid. The object is then removed and placed in another container, filled with a less dense liquid. What would you observe? You did not open hints for this part. ANSWER: Part G Two objects, T and B, have identical size and shape and have uniform density. They are carefully placed in a container filled with a liquid. Both objects float in equilibrium. Less of object T is submerged than of object B, which floats, fully submerged, closer to the bottom of the container. Which of the following statements is true? ANSWER: The object would sink all the way to the bottom. The object would float submerged more deeply than in the first container. The object would float submerged less deeply than in the first container. More than one of these outcomes is possible. The object would sink all the way to the bottom. The object would float submerged more deeply than in the first container. The object would float submerged less deeply than in the first container. More than one of these outcomes is possible. Object T has a greater density than object B. Object B has a greater density than object T. Both objects have the same density. ± Buoyant Force Conceptual Question A rectangular wooden block of weight floats with exactly one-half of its volume below the waterline. Part A What is the buoyant force acting on the block? You did not open hints for this part. ANSWER: Part B W The buoyant force cannot be determined. 2W W 1 W 2 The density of water is 1.00 . What is the density of the block? You did not open hints for this part. ANSWER: Part C This question will be shown after you complete previous question(s). 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). g/cm3 2.00 between 1.00 and 2.00 1.00 between 0.50 and 1.00 0.50 The density cannot be determined. g/cm3 g/cm3 g/cm3 g/cm3 g/cm3 Flow Velocity of Blood Conceptual Question Arteriosclerotic plaques forming on the inner walls of arteries can decrease the effective cross-sectional area of an artery. Even small changes in the effective area of an artery can lead to very large changes in the blood pressure in the artery and possibly to the collapse of the blood vessel. Imagine a healthy artery, with blood flow velocity of and mass per unit volume of . The kinetic energy per unit volume of blood is given by Imagine that plaque has narrowed an artery to one-fifth of its normal cross-sectional area (an 80% blockage). Part A Compared to normal blood flow velocity, , what is the velocity of blood as it passes through this blockage? You did not open hints for this part. ANSWER: Part B This question will be shown after you complete previous question(s). Part C v0 = 0.14 m/s  = 1050 kg/m3 K0 =  . 1 2 v20 v0 80v0 20v0 5v0 v0/5 This question will be shown after you complete previous question(s). For parts D – F imagine that plaque has grown to a 90% blockage. 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). ± Playing with a Water Hose Two children, Ferdinand and Isabella, are playing with a water hose on a sunny summer day. Isabella is holding the hose in her hand 1.0 meters above the ground and is trying to spray Ferdinand, who is standing 10.0 meters away. Part A Will Isabella be able to spray Ferdinand if the water is flowing out of the hose at a constant speed of 3.5 meters per second? Assume that the hose is pointed parallel to the ground and take the magnitude of the acceleration due to gravity to be 9.81 meters per second, per second. You did not open hints for this part. v0 g ANSWER: Part B This question will be shown after you complete previous question(s). Tactics Box 15.2 Finding Whether an Object Floats or Sinks Learning Goal: To practice Tactics Box 15.2 Finding whether an object floats or sinks. If you hold an object underwater and then release it, it can float to the surface, sink, or remain “hanging” in the water, depending on whether the fluid density is larger than, smaller than, or equal to the object’s average density . These conditions are summarized in this Tactics Box. Yes No f avg TACTICS BOX 15.2 Finding whether an object floats or sinks Object sinks Object floats Object has neutral buoyancy An object sinks if it weighs more than the fluid it displaces, that is, if its average density is greater than the density of the fluid: . An object floats on the surface if it weighs less than the fluid it displaces, that is, if its average density is less than the density of the fluid: . An object hangs motionless in the fluid if it weighs exactly the same as the fluid it displaces. It has neutral buoyancy if its average density equals the density of the fluid: . Part A Ice at 0.0 has a density of 917 . A 3.00 ice cube is gently released inside a small container filled with oil and is observed to be neutrally buoyant. What is the density of the oil, ? Express your answer in kilograms per meter cubed to three significant figures. ANSWER: Part B Once the ice cube melts, what happens to the liquid water that it produces? You did not open hints for this part. ANSWER: avg > f avg < f avg = f 'C kg/m3 cm3 oil oil = kg/m3 Part C What happens if some ethyl alcohol of density 790 is poured into the container after the ice cube has melted? ANSWER: Score Summary: Your score on this assignment is 0%. You received 0 out of a possible total of 0 points. The liquid water sinks to the bottom of the container. The liquid water rises to the surface and floats on top of the oil. The liquid water is in static equilibrium at the location where the ice cube was originally placed. kg/m3 A layer of ethyl alcohol forms between the oil and the water. The layer of ethyl alcohol forms at the bottom of the container. The layer of ethyl alcohol forms on the surface.

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