Name: Period: Dynamics-Friction 36. What is the magnitude of the force needed to keep a 40. An 80-kilogram skier slides on waxed skis along a 60-newton rubber block moving across level, dry as- horizontal surface of snow at constant velocity while phalt in a straight line at a constant speed of 2 meters pushing with his poles. What is the horizontal com- per second? ponent of the force pushing him forward? 1. 40 N 1. 0.05 N 2. 51 N 2. 0.4 N 3. 60 N 3. 40 N 4. 120 N 4. 4 N 37. The force required to start an object sliding across a 41. Compared to the force needed to start sliding a crate uniform horizontal surface is larger than the force re- across a rough level floor, the force needed to keep it quired to keep the object sliding at a constant velocity. sliding is The magnitudes of the required forces are different in 1. less these situations because the force of kinetic friction 2. greater 1. is greater than the force of static friction 3. the same 2. is less than the force of static friction 3. increases as the speed of the object relative to the 42. A 1500-kilogram car accelerates at 5 meters per sec- surface increases ond2 on a level, dry, asphalt road. Determine the mag- 4. decreases as the speed of the object relative to the nitude of the net horizontal force acting on the car. surface increases 38. The diagram below shows a block sliding down a plane inclined at angle θ with the horizontal. As angle θ is increased, the coefficient of kinetic fric- 43. A 0.50-kilogram puck sliding on a horizontal shuffle- tion between the bottom surface of the block and the board court is slowed to rest by a frictional force of 1.2 surface of the incline will newtons. What is the coefficient of kinetic friction 1. decrease between the puck and the surface of the shuffleboard 2. increase court? 3. remain the same 1. 0.24 2. 0.42 39. An airplane is moving with a constant velocity in 3. 0.60 level flight. Compare the magnitude of the forward 4. 4.1 force provided by the engines to the magnitude of the backward frictional drag force. 44. An 8.0-newton wooden block slides across a hori- zontal wooden floor at constant velocity. What is the APlusPhysics: Dynamics-Friction magnitude of the force of kinetic friction between the block and the floor? 1. 2.4 N 2. 3.4 N 3. 8.0 N 4. 27 N DYN.D1 Page 51
Name: Period: Dynamics-Friction Base your answers to questions 45 through 47 on the Base your answers to questions 48 through 51 on the information below and your knowledge of physics. information below and your knowledge of physics. A horizontal 20-newton force is applied to a 5.0-kilogram The diagram below represents a 4.0-newton force applied box to push it across a rough, horizontal floor at a constant to a 0.200-kilogram copper block sliding to the right on a velocity of 3.0 meters per second to the right. horizontal steel table. 45. Determine the magnitude of the force of friction acting on the box. 48. Determine the weight of the block. 46. Calculate the weight of the box. [Show all work, 49. Calculate the magnitude of the force of friction acting including the equation and substitution with units.] on the moving block. [Show all work, including the equation and substitution with units.] 47. Calculate the coefficient of kinetic friction between 50. Determine the magnitude of the net force acting on the box and the floor. [Show all work, including the the moving block. equation and substitution with units.] 51. Describe what happens to the magnitude of the velocity of the block as the block slides across the table. Page 52 DYN.D1 APlusPhysics: Dynamics-Friction
Name: Period: Dynamics-Ramps and Inclines 1. The diagram at right represents a block at rest on an incline. Which diagram below best represents the forces acting on the block? (Ff = frictional force, FN = normal force, and Fw = weight.) 2. The diagram below shows a 50-kilogram crate on a 4. A block weighing 10 newtons is on a ramp inclined frictionless plane at angle θ to the horizontal. The at 30° to the horizontal. A 3-newton force of fric- crate is pushed at constant speed up the incline from tion, Ff, acts on the block as it is pulled up the ramp point A to point B by force F. at constant velocity with force F, which is parallel to the ramp, as shown in the diagram below. If angle θ were increased, what would be the effect What is the magnitude of force F? on the magnitude of force F and the total work W 1. 7 N done on the crate as it is moved from A to B? 2. 8 N 1. W would remain the same and the magnitude of 3. 10 N 4. 13 N F would decrease. 2. W would remain the same and the magnitude of 5. The diagram below shows a 1.0 × 105-newton truck at rest on a hill that makes an angle of 8.0° with the F would increase. horizontal. 3. W would increase and the magnitude of F would decrease. 4. W would increase and the magnitude of F would increase. 3. In the diagram below, a 10-kilogram block is at rest on a plane inclined at 15° to the horizontal. As the angle of the incline is increased to 30°, the What is the component of the truck’s weight parallel mass of the block will to the hill? 1. decrease 1. 1.4 × 103 N 2. increase 2. 1.0 × 104 N 3. remain the same 3. 1.4 × 104 N 4. 9.9 × 104 N APlusPhysics: Dynamics-Ramps and Inclines DYN.B3 Page 53
Name: Period: Dynamics-Ramps and Inclines 6. The diagram below shows a sled and rider sliding down a snow-covered hill that makes an angle of 30° with the horizontal. Which vector best represents the direction of the normal force, FN, exerted by the hill on the sled? 7. Three forces act on a box on an inclined plane as 1. 0 N shown in the diagram below. [Vectors are not drawn 2. 2.1 N to scale.] 3. 7.7 N 4. 8.0 N If the box is at rest, the net force acting on it is equal to 1. the weight 2. the normal force 3. friction 4. zero 8. An 8.0-newton block is accelerating down a friction- less ramp inclined at 15° to the horizontal, as shown in the diagram below. What is the magnitude of the net force causing the block’s acceleration? Page 54 DYN.B3 APlusPhysics: Dynamics-Ramps and Inclines
Name: Period: UCM-Circular Motion Base your answers to questions 1 and 2 on the informa- 5. A car travels at constant speed around a section of tion and diagram below. horizontal, circular track. On the diagram below, draw an arrow at point P to represent the direction The diagram shows the top view of a 65-kilogram student of the centripetal acceleration of the car when it is at at point A on an amusement park ride. The ride spins point P. the student in a horizontal circle of radius 2.5 meters, at a constant speed of 8.6 meters per second. The floor is lowered and the student remains against the wall without falling to the floor. 1. Which vector best represents the direction of the cen- 6. A child is riding on a merry-go-round. As the speed tripetal acceleration of the student at point A? of the merry-go-round is doubled, the magnitude of the centripetal force acting on the child 1. remains the same 2. is doubled 3. is halved 4. is quadrupled 2. The magnitude of the centripetal force acting on the 7. A ball attached to a string is moved at constant speed student at point A is approximately in a horizontal circular path. A target is located near 1. 1.2 × 104 N the path of the ball as shown in the diagram. 2. 1.9 × 103 N 3. 2.2 × 102 N 4. 3.0 × 101 N 3. The magnitude of the centripetal force acting on an At which point along the ball’s path should the string object traveling in a horizontal, circular path will de- be released, if the ball is to hit the target? crease if the 1. A 1. radius of the path is increased 2. B 2. mass of the object is increased 3. C 3. direction of motion of the object is reversed 4. D 4. speed of the object is increased 8. Which unit is equivalent to meters per second? 4. Centripetal force FC acts on a car going around a 1. Hz∙s curve. If the speed of the car were twice as great, the 2. Hz∙m magnitude of the centripetal force necessary to keep 3. s/Hz the car moving in the same path would be 4. m/Hz 1. FC 2. 2FC 3. FC/2 4. 4FC APlusPhysics: UCM-Circular Motion UCM.A1, UCM.A2, UCM.A3 Page 55
Name: Period: UCM-Circular Motion 9. The diagram at right shows an object moving counterclockwise around a horizontal, circular track. Which diagram represents the direction of both the object’s velocity and the centrip- etal force acting on the object when it is in the position shown? 10. Which graph best represents the relationship between the magnitude of the centripetal acceleration and the speed of an object moving in a circle of constant radius? Base your answers to questions 11 through 13 on the information and data table below. In an experiment, a student measured the length and period of a simple pen- dulum. The data table lists the length (l) of the pendulum in meters and the square of the period (T2) of the pendu- lum in seconds2. 11. Using the information in the data table, construct a graph on the grid provided by plotting the data points for the square of period versus length, and then drawing the best-fit straight line. 12. Using your graph, determine the time in seconds it would take this pen- dulum to make one complete swing if it were 0.200 meter long. 13. The period of a pendulum is related to its length by the formula: ⎛⎝⎜⎜⎜⎜ ⎠⎟⎟⎟⎟⎞• T 2 = 4π2 l If g represents the acceleration due to gravity, explain g how the graph you have drawn could be used to calculate the value of g. Page 56 UCM.A1, UCM.A2, UCM.A3 APlusPhysics: UCM-Circular Motion
Name: Period: UCM-Circular Motion 14. A 1.0 × 103-kilogram car travels at a constant speed of 20 meters per second around a horizontal circular track. Which diagram correctly represents the direction of the car’s velocity (v) and the direction of the centripetal force (FC) acting on the car at one particular moment? 15. A baby and a stroller have a total mass of 20 ki- 17. In the diagram below, S is a point on a car tire rotat- lograms. A force of 36 newtons keeps the ing at a constant rate. stroller moving in a circular path with a radius of 5.0 meters. Calculate the Which graph best represents the magnitude of the speed at which the stroller moves centripetal acceleration of point S as a function of around the curve. [Show all work, time? including the equation and substi- tution with units.] 16. The diagram below shows a 5.0-kilogram bucket of water being swung in a horizontal circle of 0.70-me- ter radius at a constant speed of 2.0 meters per second. The magnitude of the centripetal force on the bucket 18. A 0.50-kilogram object moves in a horizontal cir- of water is approximately cular path with a radius of 0.25 meter at a constant 1. 5.7 N speed of 4.0 meters per second. What is the magni- 2. 14 N tude of the object’s acceleration? 3. 29 N 1. 8.0 m/s2 4. 200 N 2. 16 m/s2 3. 32 m/s2 APlusPhysics: UCM-Circular Motion 4. 64 m/s2 UCM.A1, UCM.A2, UCM.A3 Page 57
Name: Period: UCM-Circular Motion Base your answers to questions 19 and 20 on the informa- Base your answers to questions 22 and 23 on the informa- tion below. tion below. A go-cart travels around a flat, horizontal, circular track In an experiment, a 0.028-kilogram rubber stopper is at- with a radius of 25 meters. The mass of the go-cart with tached to one end of a string. A student whirls the stopper the rider is 200 kilograms. The magnitude of the maxi- overhead in a horizontal circle with a radius of 1.0 meter. mum centripetal force exerted by the track on the go-cart The stopper completes 10 revolutions in 10 seconds. is 1200 newtons. 19. What is the maximum speed the 200-kilogram go- cart can travel without sliding off the track? 1. 8.0 m/s 2. 12 m/s 3. 150 m/s 4. 170 m/s 20. Which change would increase the maximum speed 22. Determine the speed of the whirling stopper. at which the go-cart could travel without sliding off this track? 23. Calculate the magnitude of the centripetal force on 1. Decrease the coefficient of friction between the the whirling stopper. [Show all work, including the go-cart and the track. equation and substitution with units.] 2. Decrease the radius of the track. 3. Increase the radius of the track. 4. Increase the mass of the go-cart. 21. A car moves with a constant speed in a clockwise di- rection around a circular path of radius r, as repre- sented in the diagram below. 24. The diagram below represents a mass, m, being swung clockwise at constant speed in a horizontal circle. When the car is in the position shown, its accelera- At the instant shown, the centripetal force acting on tion is directed toward the mass m is directed toward point 1. north 1. A 2. west 2. B 3. south 3. C 4. east 4. D Page 58 UCM.A1, UCM.A2, UCM.A3 APlusPhysics: UCM-Circular Motion
Name: Period: UCM-Circular Motion Base your answers to questions 25 and 26 on the informa- Base your answers to questions 29 through 31 on the in- tion below. formation below. A 2.0 × 103-kilogram car travels at a constant speed of The combined mass of a race car and its 12 meters per second around a circular curve of radius 30 driver is 600 kilograms. Traveling at meters. constant speed, the car completes one lap around a circular track 25. What is the magnitude of the centripetal acceleration of radius 160 meters in 36 of the car as it goes around the curve? seconds. 1. 0.40 m/s2 2. 4.8 m/s2 29. Calculate the speed of the car. [Show all work, in- 3. 800 m/s2 cluding the equation and substitution with units.] 4. 9,600 m/s2 26. As the car goes around the curve, the centripetal force 30. On the diagram below, draw an arrow to represent the is directed direction of the net force acting on the car when it is 1. toward the center of the circular curve in position A. 2. away from the center of the circular curve 3. tangent to the curve in the direction of motion 4. tangent to the curve opposite the direction of motion 27. A car round a horizontal curve of constant radius at a constant speed. Which diagram best represents the directions of both the car’s velocity, v, and accelera- tion, a? 31. Calculate the magnitude of the centripetal accelera- tion of the car. [Show all work, including the equa- tion and substitution with units.] 28. A 1750-kilogram car travels at a constant speed of 15 32. A ball of mass M at the end of a string is swung in a meters per second around a horizontal circular track horizontal circular path of radius R at constant speed with a radius of 45 meters. The magnitude of the cen- V. Which combination of changes would require the tripetal force acting on the car is greatest increase in the centripetal force acting on 1. 5 N the ball? 2. 583 N 1. doubling V and doubling R 3. 8750 N 2. doubling V and halving R 4. 3.94 × 105 N 3. halving V and doubling R 4. halving V and halving R APlusPhysics: UCM-Circular Motion UCM.A1, UCM.A2, UCM.A3 Page 59
Name: Period: UCM-Circular Motion Base your answers to questions 33 through 36 on the information and table below. In a laboratory exercise, a student kept the mass and amplitude of swing of a simple pendulum constant. The length of the pendulum was increased and the period of the pendulum was measured. The student recorded the data in the table. You are to construct a graph on the grid provided following the directions below. 33. Label each axis with the appropriate physical quantity and unit, and mark an appropriate scale on each axis. 34. Plot the data points for period versus pendulum length. 35. Draw the best-fit line or curve for the data graphed. 36. Using your graph, determine the period of a pen- dulum whose length is 0.25 meter. 37. In the diagram below, a cart travels clockwise at 38. The centripetal force acting on the space shuttle as it constant speed in a horizontal circle. orbits Earth is equal to the shuttle’s 1. inertia 2. momentum 3. velocity 4. weight At the position shown in the diagram, which arrow indicates the direction of the centripetal acceleration of the cart? 1. A 2. B 3. C 4. D Page 60 UCM.A1, UCM.A2, UCM.A3 APlusPhysics: UCM-Circular Motion
Name: Period: UCM-Circular Motion Base your answers to questions 39 through 42 on the in- 42. The rubber stopper is now whirled in a vertical circle formation and diagram below. at the same speed. On the diagram, draw and label vectors to indicate the direction of the weight (Fg) In an experiment, a rubber stopper is attached to one and the direction of the centripetal force (FC) at the end of a string that is passed through a plastic tube be- position shown. fore weights are attached to the other end. The stopper is whirled in a horizontal circular path at constant speed. 39. On the diagram of the top view (below), draw the 43. An unbalanced force of 40 newtons keeps a 5.0-kilo- path of the rubber stopper if the string breaks at the gram object traveling in a circle of radius 2.0 meters. position shown. What is the speed of the object? 1. 8.0 m/s 2. 2.0 m/s 3. 16 m/s 4. 4.0 m/s 40. Describe what would happen to the radius of the cir- 44. A student on an amusement park ride moves in a cir- cle if the student whirls the stopper at a greater speed cular path with a radius of 3.5 meters once every 8.9 without changing the balancing weights. seconds. The student moves at an average speed of 1. 0.39 m/s 41. List three measurements that must be taken to show 2. 1.2 m/s that the magnitude of the centripetal force is equal to 3. 2.5 m/s the balancing weights. 4. 4.3 m/s 45. A stone on the end of a string is whirled clockwise at constant speed in a horizontal circle as shown in the diagram. Which pair of arrows best represents the directions of the stone’s velocity, v, and acceleration, a, at the position shown? APlusPhysics: UCM-Circular Motion UCM.A1, UCM.A2, UCM.A3 Page 61
Name: Period: UCM-Circular Motion Base your answers to questions 46 and 47 on the infor- Base your answers to questions 49 and 50 on the infor- mation below. mation and diagram below. A 28-gram rubber stopper is attached to a string and A 1.5 × 103-kg car is driven at a constant speed of 12 whirled clockwise in a horizontal circle with a radius of meters per second counterclockwise around a horizontal 0.80 meter. The diagram in your answer booklet rep- circular track having a radius of 50 meters, as represented resents the motion of the rubber stopper. The stopper below. maintains a constant speed of 2.5 meters per second. 46. Calculate the magnitude of the centripetal accelera- tion of the stopper. [Show all work, including the equation and substitution with units.] 47. On the diagram below, draw an arrow showing the 49. On the diagram above, draw a vector to indicate the direction of the centripetal force acting on the stopper direction of the velocity of the car when it is at the when it is at the position shown. position shown. Start the arrow on the car. 50. Calculate the magnitude of the centripetal acceleration of the car. [Show all work, including the equation and substitution with units. 51. A body, B, is moving at constant speed in a horizontal circular path around point P. Which diagram shows the direction of the velocity (v) and the direction of the centripetal force (Fc) acting on the body? 48. A 1.0 × 103-kilogram car travels at a constant speed of 20 meters per second around a horizontal circular track. The diameter of the track is 1.0 × 102 meters. The magnitude of the car’s centripetal acceleration is 1. 0.20 m/s2 2. 2.0 m/s2 3. 8.0 m/s2 4. 4.0 m/s2 Page 62 UCM.A1, UCM.A2, UCM.A3 APlusPhysics: UCM-Circular Motion
Name: Period: UCM-Circular Motion 52. A boy pushes his sister on a swing. What is the frequency of oscillation of his sister on the swing if the boy counts 90 complete swings in 300 seconds? 1. 0.30 Hz 2. 2.0 Hz 3. 1.5 Hz 4. 18 Hz APlusPhysics: UCM-Circular Motion UCM.A1, UCM.A2, UCM.A3 Page 63
Name: Period: UCM-Gravity 1. A space probe is launched into space from Earth’s surface. Which graph represents the relationship between the magnitude of the gravitational force exerted on Earth by the space probe and the distance between the space probe and the center of Earth? 2. The diagram shows two bowling balls, A and B, each 6. A container of rocks with a mass of 65 kilograms is having a mass of 7 kilograms, placed 2 meters apart. brought back from the Moon’s surface where the ac- celeration due to gravity is 1.62 meters per second2. What is the magnitude of the gravitational force What is the weight of the container of rocks on exerted by ball A on ball B? Earth’s surface? 1. 8.17 × 10-9 N 1. 638 N 2. 1.63 × 10-9 N 2. 394 N 3. 8.17 × 10-10 N 3. 105 N 4. 1.17 × 10-10 N 4. 65 N 7. The graph below represents the relationship between gravitational force and mass for objects near the surface of Earth. 3. A 60-kg physics student would weigh 1560 N on the surface of planet X. What is the magnitude of the acceleration due to gravity on the surface of planet X? 1. 0.038 m/s2 2. 6.1 m/s2 3. 9.8 m/s2 4. 26 m/s2 4. Earth’s mass is approximately 81 times the mass of The slope of the graph represents the the Moon. If Earth exerts a gravitational force of 1. acceleration due to gravity magnitude F on the Moon, the magnitude of the 2. universal gravitational constant gravitational force of the Moon on Earth is 3. momentum of objects 1. F 4. weight of objects 2. F/81 3. 9F 8. A person weighing 785 newtons on the surface of 4. 81F Earth would weigh 298 newtons on the surface of Mars. What is the magnitude of the gravitational 5. An object weighs 100 newtons on Earth’s surface. field strength on the surface of Mars? When it is moved to a point one Earth radius above 1. 2.63 N/kg Earth’s surface, it will weigh 2. 3.72 N/kg 1. 25 N 3. 6.09 N/kg 2. 50 N 4. 9.81 N/kg 3. 100 N 4. 400 N Page 64 UCM.B1 APlusPhysics: UCM-Gravity
Name: Period: UCM-Gravity Base your answers to questions 9 through 11 on the passage and data table below. The net force on a planet is due primarily to the other planets and the Sun. By taking into account all the forces acting on a planet, investigators calculated the orbit of each planet. A small discrepancy between the calculated orbit and the observed orbit of the planet Uranus was noted. It ap- peared that the sum of the forces on Uranus did not equal its mass times its acceleration, unless there was another force on the planet that was not included in the calculation. Assuming that this force was exerted by an unobserved planet, two scientists working independently calculated where this unknown planet must be in order to account for the dis- crepancy. Astronomers pointed their telescopes in the predicted direction and found the planet we now call Neptune. 9. What fundamental force is the author referring to in this passage as a force between planets? 10. The diagram at right represents Neptune, Uranus, and the Sun in a straight line. Neptune is 1.63 × 1012 meters from Uranus. Calculate the magnitude of the interplanetary force of attraction between Uranus and Neptune at this point. [Show all work, in- cluding the equation and substitution with units.] 11. The magnitude of the force the Sun exerts on Uranus is 1.41 × 1021 newtons. Explain how it is possible for the Sun to exert a greater force on Uranus than Neptune exerts on Uranus. 12. When Earth and the Moon are separated by a dis- 13. An astronaut weighs 8.00 × 102 newtons on the sur- tance of 3.84 × 108 meters, the magnitude of the grav- face of Earth. What is the weight of the astronaut itational force of attraction between them is 2.0 × 1020 6.37 × 106 meters above the surface of Earth? newtons. What would be the magnitude of this grav- 1. 0.00 N itational force of attraction if Earth and the Moon 2. 2.00 × 102 N were separated by a distance of 1.92 × 108 meters? 3. 1.60 × 103 N 1. 5.0 × 1019 N 4. 3.20 × 103 N 2. 2.0 × 1020 N 3. 4.0 × 1020 N 4. 8.0 × 1020 N APlusPhysics: UCM-Gravity UCM.B1 Page 65
Name: Period: UCM-Gravity Base your answers to questions 14 and 15 on the informa- 18. A 5.0-kilogram sphere, starting from rest, falls freely tion and table below. 22 meters in 3.0 seconds near the surface of a plan- et. Compared to the acceleration due to gravity near The weight of an object was determined at five different Earth’s surface, the acceleration due to gravity near distances from the center of Earth. The results are shown the surface of the planet is approximately in the table below. Position A represents results for the 1. the same object at the surface of Earth. 2. twice as great 3. one-half as great 4. four times as great 19. Which diagram best represents the gravitational field lines surrounding Earth? 14. The approximate mass of the object is 1. 0.01 kg 2. 10 kg 3. 100 kg 4. 1,000 kg 15. At what distance from the center of Earth is the 20. The diagram below represents two satellites of equal weight of the object approximately 28 newtons? mass, A and B, in circular orbits around a planet. 1. 3.5 × 107 m 2. 3.8 × 107 m 3. 4.1 × 107 m 4. 4.5 × 107 m 16. Gravitational forces differ from electrostatic forces in that gravitational forces are 1. attractive, only 2. repulsive, only 3. neither attractive nor repulsive 4. both attractive and repulsive 17. The gravitational force of attraction between Earth and the Sun is 3.52 × 1022 newtons. Calculate the mass of the Sun. [Show all work, including the equa- tion and substitution with units.] Page 66 UCM.B1 Compared to the magnitude of the gravitational force of attraction between satellite A and the planet, the magnitude of the gravitational force of attraction between satellite B and the planet is 1. half as great 2. twice as great 3. one-fourth as great 4. four times as great APlusPhysics: UCM-Gravity
Name: Period: UCM-Gravity Base your answers to questions 21 and 22 on the informa- 24. Two physics students have been selected by NASA tion below. [Show all work, including the equation and to accompany astronauts on a future mission to the substitution with units.] Moon. The students are to design and carry out a simple experiment to measure the acceleration due to Io (pronounced “EYE oh”) is one of Jupiter’s moons dis- gravity on the surface of the Moon. covered by Galileo. Io is slightly larger than Earth’s Moon. Describe an experiment that the students could con- duct to measure the acceleration due to gravity on the The mass of Io is 8.93 × 1022 kilograms Moon. Your description must include: and the mass of Jupiter is 1.90 × 1027 • the equipment needed kilograms. The distance between the • what quantities would be measured using the centers of Io and Jupiter is 4.22 × 108 meters. equipment 21. Calculate the magnitude of the gravitational force of • what procedure the students should follow in attraction that Jupiter exerts on Io. conducting their experiment • what equations and/or calculations the students would need to do to arrive at a value for the ac- celeration due to gravity on the Moon. 22. Calculate the magnitude of the acceleration of Io due to the gravitational force exerted by Jupiter. 23. Which diagram best represents the gravitational forc- es, Fg, between a satellite, S, and Earth? 25. As a meteor moves from a distance of 16 Earth radii to a distance of 2 Earth radii from the center of Earth, the magnitude of the gravitational force between the meteor and Earth becomes 1. 1/8 as great 2. 8 times as great 3. 64 times as great 4. 4 times as great APlusPhysics: UCM-Gravity UCM.B1 Page 67
Name: Period: UCM-Gravity 26. A 25-kilogram space probe fell freely with an accel- 32. A 1200-kilogram space vehicle travels at 4.8 meters eration of 2 meters per second2 just before it landed per second along the level surface of Mars. If the on a distant planet. What is the weight of the space magnitude of the gravitational field strength on the probe on that planet? surface of Mars is 3.7 newtons per kilogram, the mag- 1. 12.5 N nitude of the normal force acting on the vehicle is 2. 25 N 1. 320 N 3. 50 N 2. 930 N 4. 250 N 3. 4400 N 4. 5800 N 27. The acceleration due to gravity on the surface of planet X is 19.6 meters per second2. If an object on 33. What is the weight of a 2.00-kilogram object on the the surface of this planet weighs 980 newtons, the surface of Earth? mass of the object is 1. 4.91 N 1. 50 kg 2. 2.00 N 2. 100 kg 3. 9.81 N 3. 490 N 4. 19.6 N 4. 908 N 34. A 2.0-kilogram object is falling freely near Earth’s 28. What is the acceleration due to gravity at a location surface. What is the magnitude of the gravitational where a 15-kilogram mass weighs 45 newtons? force that Earth exerts on the object? 1. 675 m/s2 1. 20 N 2. 9.81 m/s2 2. 2.0 N 3. 3.00 m/s2 3. 0.20 N 4. 0.333 m/s2 4. 0.0 N 29. As an astronaut travels from the surface of Earth 35. Calculate the magnitude of the centripetal force act- to a position that is four times as far away from the ing on Earth as it orbits the Sun, assuming a circular center of Earth, the astronaut’s orbit and an orbital speed of 3.00 × 104 meters per 1. mass decreases second. [Show all work, including the equation and 2. mass remains the same substitution with units.] 3. weight increases 4. weight remains the same 36. On a small planet, an astronaut uses a vertical force of 175 newtons to lift an 87.5-kilogram boulder at 30. A satellite weighs 200 newtons on the surface of constant velocity to a height of 0.350 meter above Earth. What is its weight at a distance of one Earth the planet’s surface. What is the magnitude of the radius above the surface of Earth? gravitational field strength on the surface of the 1. 50 N planet? 2. 100 N 1. 0.500 N/kg 3. 400 N 2. 2.00 N/kg 4. 800 N 3. 9.81 N/kg 4. 61.3 N/kg 31. A 2.00-kilogram object weighs 19.6 newtons on Earth. If the acceleration due to gravity on Mars is 37. Calculate the magnitude of the average gravitational 3.71 meters per second2, what is the object’s mass on force between Earth and Moon. [Show all work, Mars? including the equation and substitution with units.] 1. 2.64 kg 2. 2.00 kg APlusPhysics: UCM-Gravity 3. 19.6 N 4. 7.42 N Page 68 UCM.B1
Name: Period: UCM-Gravity 38. Which graph represents the relationship between the 40. At a certain location, a gravitational force with a magnitude of the gravitational force exerted by Earth magnitude of 350 newtons acts on a 70-kilogram as- on a spacecraft and the distance between the center of tronaut. What is the magnitude of the gravitational the spacecraft and center of Earth? [Assume constant field strength at this location? mass for the spacecraft.] 1. 0.20 kg/N 2. 5.0 N/kg 3. 9.8 m/s2 4. 25,000 N•kg 41. Which graph represents the relationship between the magnitude of the gravitational force, Fg, between two masses and the distance, r, between the centers of the masses? 39. In which diagram do the field lines best represent 42. A 2.0-kilogram mass is located 3.0 meters above the the gravitational field around Earth? surface of Earth. What is the magnitude of Earth’s gravitational field strength at this location? 1. 4.9 N/kg 2. 2.0 N/kg 3. 9.8 N/kg 4. 20 N/kg APlusPhysics: UCM-Gravity UCM.B1 Page 69
Name: Period: UCM-Gravity Base your answers to questions 43 through 45 on the information below and on your knowledge of physics. [Show all work, including the equation and substitution with units.] Pluto orbits the Sun at an average distance of 5.91 × 1012 meters. Pluto’s diameter is 2.30 × 106 meters and its mass is 1.31 × 1022 kilograms. Charon orbits Pluto with their centers separated by a distance of 1.96 × 107 meters. Charon has a diameter of 1.21 × 106 meters and a mass of 1.55 × 1021 kilograms. 43. Calculate the magnitude of the gravitational force of attraction that Pluto exerts on Charon. 44. Calculate the magnitude of the acceleration of Charon toward Pluto. 45. State the reason why the magnitude of the Sun’s gravitational force on Pluto is greater than the magnitude of the Sun’s gravitational force on Charon. 46. The Hubble telescope’s orbit is 5.6 × 105 meters above Earth’s surface. The telescope has a mass of 1.1 × 104 kilograms. Earth exerts a gravitational force of 9.1 × 104 newtons on the telescope. The magnitude of Earth’s gravitational field strength at this location is 1. 1.5 × 10-20 N/kg 2. 0.12 N/kg 3. 8.3 N/kg 4. 9.8 N/kg Page 70 UCM.B1 APlusPhysics: UCM-Gravity
Name: Period: Momentum-Impulse 1. A 1,200-kilogram car traveling at 10 meters per sec- 5. What is the speed of a 1.0 × 103-kilogram car that ond hits a tree and is brought to rest in 0.10 second. has a momentum of 2.0 × 104 kilogram∙meters per What is the magnitude of the average force acting second east? on the car to bring it to rest? 1. 5.0 × 10-2 m/s 1. 1.2 × 102 N 2. 2.0 × 101 m/s 2. 1.2 × 103 N 3. 1.0 × 104 m/s 3. 1.2 × 104 N 4. 2.0 × 107 m/s 4. 1.2 × 105 N 6. A motorcycle being driven on a dirt path hits a rock. 2. A 50-kilogram student threw a 0.40-kilogram ball It’s 60-kilogram cyclist is projected over the handle- with a speed of 20 meters per second. What was the bars at 20 meters per second into a haystack. if the magnitude of the impulse that the student exerted cyclist is brought to rest in 0.50 second, the magni- on the ball? tude of the average force exerted on the cyclist by the 1. 8.0 N∙s haystack is 2. 78 N∙s 1. 6.0 × 101 N 3. 4.0 × 102 N∙s 2. 5.9 × 102 N 4. 1.0 × 103 N∙s 3. 1.2 × 103 N 4. 2.4 × 103 N 3. In the diagram below, a 60-kilogram rollerskater ex- erts a 10-newton force on a 30-kilogram rollerskater 7. A 70-kilogram hockey player skating east on an ice for 0.20 second. rink is hit by a 0.1-kilogram hockey puck moving to- ward the west. The puck exerts a 50-newton force toward the west on the player. Determine the mag- nitude of the force that the player exerts on the puck during this collision. What is the magnitude of the impulse applied to the 8. Which situation will produce the greatest change of 30-kilogram rollerskater? momentum for a 1.0-kilogram cart? 1. 50 N∙s 1. accelerating it from rest to 3.0 m/s 2. 2.0 N∙s 2. accelerating it from 2.0 m/s to 4.0 m/s 3. 6.0 N∙s 3. applying a net force of 5.0 N for 2.0 s 4. 12 N∙s 4. applying a net force of 10.0 N for 0.5 s 4. Two carts are pushed apart by an expanding spring, as shown in the diagram below. If the average force on the 1-kilogram cart is 1 9. A 0.149-kilogram baseball, initially moving at 15 me- newton, what is the average force on the 2-kilogram ters per second, is brought to rest in 0.040 second by cart? a baseball glove on a catcher’s hand. The magnitude 1. 1 N of the average force exerted on the ball by the glove is 2. 0.0 N 1. 2.2 N 3. 0.5 N 2. 2.9 N 4. 4 N 3. 17 N 4. 56 N APlusPhysics: Momentum-Impulse MOM.A1, MOM.A2, MOM.A3 Page 71
Name: Period: Momentum-Impulse 10. Calculate the magnitude of the impulse applied to a 15. Cart A has a mass of 2 kilograms and a speed of 3 0.75-kilogram cart to change its velocity from 0.50 meters per second. Cart B has a mass of 3 kilograms meter per second east to 2.00 meters per second east. and a speed of 2 meters per second. Compared to the [Show all work, including the equation and substitu- inertia and magnitude of momentum of cart A, cart tion with units.] B has 1. the same inertia and a smaller magnitude of mo- 11. Which is a scalar quantity? mentum 1. acceleration 2. the same inertia and the same magnitude of mo- 2. momentum mentum 3. speed 3. greater inertia and a smaller magnitude of mo- 4. displacement mentum 4. greater inertia and the same magnitude of mo- 12. A 0.45-kilogram football traveling at a speed of 22 mentum meters per second is caught by an 84-kilogram sta- tionary receiver. If the football comes 16. A 6.0-kilogram block, sliding to the east across a hor- to rest in the receiver’s arms, the izontal, frictionless surface with a momentum of 30 magnitude of the impulse imparted kilogram∙meters per second, strikes an obstacle. The to the receiver by the ball is obstacle exerts an impulse of 10 newton∙seconds to 1. 1800 N∙s the west on the block. The speed of the block after 2. 9.9 N∙s the collision is 3. 4.4 N∙s 1. 1.7 m/s 4. 3.8 N∙s 2. 3.3 m/s 3. 5.0 m/s 13. A force of 6.0 newtons changes the momentum of 4. 20 m/s a moving object by 3.0 kilogram∙meters per second. How long did the force act on the mass? 17. A 60-kilogram student jumps down from a labora- 1. 1.0 s tory counter. At the instant he lands on the floor his 2. 2.0 s speed is 3 meters per second. If the student stops in 3. 0.25 s 0.2 second, what is the average force of the floor on 4. 0.50 s the student? 1. 1 × 10-2 N 14. A 1000-kilogram car traveling due east at 15 meters 2. 1 × 102 N per second is hit from behind and receives a forward 3. 9 × 102 N impulse of 6000 newton-seconds. Determine the 4. 4 N magnitude of the car’s change in momentum due to this impulse. 18. A 2.0-kilogram laboratory cart is sliding across a horizontal frictionless surface at a constant veloc- ity of 4.0 meters per second east. What will be the cart’s velocity after a 6.0-newton westward force acts on it for 2.0 seconds? 1. 2.0 m/s east 2. 2.0 m/s west 3. 10 m/s east 4. 10 m/s west Page 72 MOM.A1, MOM.A2, MOM.A3 APlusPhysics: Momentum-Impulse
Name: Period: Momentum-Impulse 19. A 40-kilogram mass is moving across a horizontal 24. A 5-kilogram block slides along a horizontal, fric- surface at 5.0 meters per second. What is the mag- tionless surface at 10 meters per second for 4 sec- nitude of the net force required to bring the mass to onds. The magnitude of the block’s momentum is a stop in 8.0 seconds? 1. 200 kg∙m/s 1. 1.0 N 2. 50 kg∙m/s 2. 5.0 N 3. 20 kg∙m/s 3. 25 N 4. 12.5 kg∙m/s 4. 40 N 25. Calculate the time required for a 6000-newton net 20. A 0.15-kilogram baseball moving at 20 meters per force to stop a 1200-kilogram car initially traveling second is stopped by a catcher in 0.010 second. The at 10 meters per second. [Show all work, including average force stopping the ball is the equation and substitution with units.] 1. 3.0 × 10-2 N 2. 3.0 × 100 N 3. 3.0 × 101 N 4. 3.0 × 102 N 21. A 2.0-kilogram body is initially traveling at a veloc- 26. Which term identifies a scalar quantity? ity of 40 meters per second east. If a constant force 1. displacement of 10 newtons due east is applied to the body for 5.0 2. momentum seconds, the final speed of the body is 3. velocity 1. 15 m/s 4. time 2. 25 m/s 3. 65 m/s 27. A baseball bat exerts an average force of 600 new- 4. 130 m/s tons east on a ball, imparting an impulse of 3.6 newton•seconds east to the ball. Calculate the 22. A 75-kilogram hockey player is skating across the amount of time the baseball bat is in contact with ice at a speed of 6.0 meters per second. What is the the ball. [Show all work, including the equation and magnitude of the average force required to stop the substitution with units.] player in 0.65 second? 1. 120 N 28. An air bag is used to safely decrease the momentum 2. 290 N of a driver in a car accident. The air bag reduces the 3. 690 N magnitude of the force acting on the driver by 4. 920 N 1. increasing the length of time the force acts on the driver 2. decreasing the distance over which the force acts on the driver 3. increasing the rate of acceleration of the driver 4. decreasing the mass of the driver 23. A bicycle and its rider have a combined mass of 80 29. A 3.0-kilogram object is acted upon by an impulse kg and a speed of 6 m/s. What is the magnitude of having a magnitude of 15 newton•seconds. What is the average force needed to bring the bicycle and its the magnitude of the object’s change in momentum rider to a stop in 4.0 seconds? due to this impulse? 1. 1.2 × 102 N 1. 5.0 kg•m/s 2. 3.2 × 102 N 2. 15 kg•m/s 3. 4.8 × 102 N 3. 3.0 kg•m/s 4. 1.9 × 103 N 4. 45 kg•m/s APlusPhysics: Momentum-Impulse MOM.A1, MOM.A2, MOM.A3 Page 73
Name: Period: Momentum-Impulse 30. A 1.5-kilogram cart initially moves at 2.0 meters per second. It is brought to rest by a constant net force in 0.30 second. What is the magnitude of the net force? 1. 0.40 N 2. 0.90 N 3. 10 N 4. 15 N 31. A 0.0600-kilogram ball traveling at 60.0 meters per second hits a concrete wall. What speed must a 0.0100-kilogram bullet have in order to hit the wall with the same magnitude of momentum as the ball? 1. 3.60 m/s 2. 6.00 m/s 3. 360 m/s 4. 600 m/s Page 74 MOM.A1, MOM.A2, MOM.A3 APlusPhysics: Momentum-Impulse
Name: Period: Momentum-Conservation 1. A 1.2-kilogram block and a 1.8-kilogram block are 4. Ball A of mass 5.0 kilograms moving at 20 meters per initially at rest on a frictionless, horizontal surface. second collides with ball B of unknown mass moving When a compressed spring between the blocks is re- at 10 meters per second in the same direction. After leased, the 1.8-kilogram block moves to the right at the collision, ball A moves at 10 meters per second 2.0 meters per second, as shown. and ball B at 15 meters per second, both still in the same direction. What is the mass of ball B? 1. 6.0 kg 2. 2.0 kg 3. 10 kg 4. 12 kg What is the speed of the 1.2-kilogram block after 5. In the diagram below, scaled vectors represent the the spring is released? momentum of each of two masses, A and B, slid- 1. 1.4 m/s ing toward each other on a frictionless, horizontal 2. 2.0 m/s surface. 3. 3.0 m/s 4. 3.6 m/s Which scaled vector best represents the momentum of the system after the masses collide? Base your answers to questions 2 and 3 on the informa- tion below. An 8.00-kilogram ball is fired horizontally from a 1.00 6. At the circus, a 100-kilogram clown × 103-kilogram cannon initially at rest. After hav- is fired 15 meters per second from a ing been fired, the momentum of the ball is 2.40 × 103 500-kilogram cannon. What is the kilogram∙meters per second east. [Neglect friction.] recoil speed of the cannon? 1. 75 m/s 2. Calculate the magnitude of the cannon’s velocity 2. 15 m/s after the ball is fired. [Show all work, including the 3. 3.0 m/s equation and substitution with units.] 4. 5.0 m/s 7. A woman with horizontal velocity v1 jumps off a dock into a stationary boat. After landing in the boat, the woman and the boat move with velocity v2. Com- pared to velocity v1, velocity v2 has 1. the same magnitude and the same direction 2. the same magnitude and the opposite direction 3. smaller magnitude and the same direction 4. larger magnitude and the same direction 3. Identify the direction of the cannon’s velocity after the ball is fired. APlusPhysics: Momentum-Conservation MOM.B1 Page 75
Name: Period: Momentum-Conservation 8. On a snow-covered road, a car with a mass of 1.1×103 11. Which two quantities can be expressed using the kilograms collides head-on with a van having a mass of same units? 2.5×103 kilograms traveling at 8.0 meters per second. 1. energy and force As a result of the collision, the vehicles lock together 2. impulse and force and immediately come to rest. Calculate the speed 3. momentum and energy of the car immediately before the collision. [Neglect 4. impulse and momentum friction.] [Show all work, including the equation and substitution with units.] 12. A 3.1-kilogram gun initially at rest is free to move. When a 0.015-kilogram bullet leaves the gun with a speed of 500 meters per second, what is the speed of the gun? 1. 0.0 m/s 2. 2.4 m/s 3. 7.5 m/s 4. 500 m/s 9. A 3.0-kilogram steel block is at rest on a frictionless Base your answers to questions 13 and 14 on the infor- horizontal surface. A 1.0-kilogram lump of clay is mation below. Show all work, including the equation propelled horizontally at 6.0 meters per second to- and substitution with units. ward the block as shown in the diagram below. A 1200-kilogram car moving at 12 meters per second collides with a 2300-kilogram car that is waiting at rest at a traffic light. After the collision, the cars lock togeth- er and slide. Eventually, the combined cars are brought to rest by a force of kinetic friction as the rubber tires slide across the dry, level asphalt road surface. 13. Calculate the speed of the locked-together cars im- mediately after the collision. Upon collision, the clay and steel block stick together and move to the right with a speed of 1. 1.5 m/s 2. 2.0 m/s 3. 3.0 m/s 4. 6.0 m/s 10. A 1.0-kilogram laboratory cart moving with a veloc- 14. Calculate the magnitude of the frictional force that ity of 0.50 meter per second due east collides with and brings the locked-together cars to rest. sticks to a similar cart initially at rest. After the colli- sion, the two carts move off together with a velocity of 0.25 meter per second due east. The total momentum of this frictionless system is 1. zero before the collision 2. zero after the collision 3. the same before and after the collision 4. greater before the collision than after the colli- sion. Page 76 MOM.B1 APlusPhysics: Momentum-Conservation
Name: Period: Momentum-Conservation 15. The diagram below represents two masses before and after they collide. Before the collision, mass mA is moving to the right with speed v, and mass mB is at rest. Upon collision, the two masses stick together. Which expression represents the speed, v’, of the masses after the collision? [Assume no outside forces are acting on mA or mB.] 16. In the diagram below, a block of mass M initially at rest on a frictionless horizontal surface is struck by a bullet of mass m moving with a horizontal velocity v. What is the velocity of the bullet-block system after the bullet embeds itself in the block? 17. When a 1.0-kilogram cart moving with a speed of 18. The diagram below shows an 8.0-kilogram cart 0.50 meter per second on a horizontal surface col- moving to the right at 4.0 meters per second about lides with a second 1.0-kilogram cart initially at rest, to make a head-on collision with a 4.0-kilogram cart the carts lock together. What is the speed of the moving to the left at 6.0 meters per second. combined carts after the collision? [Neglect friction.] 1. 1.0 m/s After the collision, the 4.0-kilogram cart moves to the 2. 0.50 m/s right at 3.0 meters per second. What is the velocity of 3. 0.25 m/s the 8.0-kilogram cart after the collision? 4. 0 m/s 1. 0.50 m/s left 2. 0.50 m/s right 3. 5.5 m/s left 4. 5.5 m/s right APlusPhysics: Momentum-Conservation MOM.B1 Page 77
Name: Period: Momentum-Conservation 19. A 7.28-kilogram bowling ball traveling 8.50 meters per second east collides head-on with a 5.45-kilo- gram bowling ball traveling 10.0 meters per second west. Determine the magnitude of the total momen- tum of the two-ball system after the collision. Page 78 MOM.B1 APlusPhysics: Momentum-Conservation
Name: Period: WEP-Work and Power 1. The work done in accelerating an object along a 5. A motor used 120 watts of power to raise a 15-new- frictionless horizontal surface is equal to the change ton object in 5.0 seconds. Through what vertical in the object’s distance was the object raised? 1. momentum 1. 1.6 m 2. velocity 2. 8.0 m 3. potential energy 3. 40 m 4. kinetic energy 4. 360 m 2. The graph below represents the relationship between 6. The diagram below shows points A, B, and C at or the work done by a student running up a flight of near Earth’s surface. As a mass is moved from A to stairs and the time of ascent. B, 100 joules of work are done against gravity. What does the slope of this graph represent? What is the amount of work done against gravity as 1. impulse an identical mass is moved from A to C? 2. momentum 1. 100 J 3. speed 2. 173 J 4. power 3. 200 J 4. 273 J 3. A student does 60 joules of work pushing a 3.0-ki- logram box up the full length of a ramp that is 5.0 7. One watt is equivalent to one meters long. What is the magnitude of the force 1. N∙m applied to the box to do this work? 2. N/m 1. 20 N 3. J∙s 2. 15 N 4. J/s 3. 12 N 4. 4.0 N 8. Two weightlifters, one 1.5 meters tall and one 2.0 meters tall, raise identical 50-kilogram masses above 4. A boat weighing 900 newtons requires a horizontal their heads. Compared to the work done by the force of 600 newtons to move it across the water at weightlifter who is 1.5 meters tall, the work done by 15 meters per second. The boat’s engine must pro- the weightlifter who is 2.0 meters tall is vide energy at the rate of 1. less 1. 2.5 × 10-2 J 2. greater 2. 4.0 × 101 W 3. the same 3. 7.5 × 103 J 4. 9.0 × 103 W 9. A 40-kilogram student runs up a staircase to a floor that is 5.0 meters higher than her starting point in APlusPhysics: WEP-Work and Power 7.0 seconds. The student’s power output is 1. 29 W 2. 280 W 3. 1.4 × 103 W 4. 1.4 × 104 W WEP.A1, WEP.A2 Page 79
Name: Period: WEP-Work and Power 10. A 3.0-kilogram block is initially at rest on a frictionless, horizontal surface. The block is moved 8.0 meters in 2.0 seconds by the application of a 12-newton horizontal force, as shown in the diagram below. What is the average power developed while moving the block? 1. 24 W 2. 32 W 3. 48 W 4. 96 W 11. The graph below shows the relationship between the 14. The work done in lifting an apple one meter near work done by a student and the time of ascent as the Earth’s surface is approximately student runs up a flight of stairs. 1. 1 J 2. 0.01 J 3. 100 J 4. 1000 J 15. A 70-kilogram cyclist develops 210 watts of power while pedaling at a constant velocity of 7.0 meters per second east. What average force is exerted east- ward on the bicycle to maintain this constant speed? 1. 490 N 2. 30 N 3. 3.0 N 4. 0 N The slope of the graph would have units of 16. A 95-kilogram student climbs 4.0 meters up a rope 1. joules in 3.0 seconds. What is the power output of the 2. seconds student? 3. watts 1. 130 W 4. newtons 2. 380 W 3. 1200 W 12. The amount of work done against friction to slide 4. 3700 W a box in a straight line across a uniform, horizontal floor depends most on the 17. Which is an SI unit for work done on an object? 1. time taken to move the box 2. distance the box is moved 1. kg • m2 3. speed of the box s2 4. direction of the box’s motion 13. What is the average power developed by a motor 2. kg • m2 as it lifts a 400-kilogram mass at a constant speed s through a vertical distance of 10 meters in 8 sec- onds? kg • m 1. 320 W 3. s 2. 500 W 3. 4,900 W 4. kg • m 4. 32,000 W s2 Page 80 WEP.A1, WEP.A2 APlusPhysics: WEP-Work and Power
Name: Period: WEP-Work and Power 18. As shown in the diagram below, a child applies a 22. Which quantity is a measure of the rate at which constant 20-newton force along the handle of a work is done? wagon which makes a 25° angle with the horizontal. 1. energy 2. power 3. momentum 4. velocity How much work does the child do in moving the 23. What is the average power required to raise a 1.81 × wagon a horizontal distance of 4.0 meters? 104-newton elevator 12.0 meters in 22.5 seconds? 1. 5.0 J 1. 8.04 × 102 W 2. 34 J 2. 9.65 × 103 W 3. 73 J 3. 2.17 × 105 W 4. 80 J 4. 4.89 × 106 W 19. Which graph best represents the relationship be- 24. A 15.0-kilogram mass is moving at 7.50 meters per tween the power required to raise an elevator and the second on a horizontal, frictionless surface. What speed at which the elevator rises? is the total work that must be done on the mass to increase its speed to 11.5 meters per second? 1. 120 J 2. 422 J 3. 570 J 4. 992 J 25. A truck weighing 3.0 × 104 newtons was driven up a hill that is 1.6 × 103 meters long to a level area that is 8.0 × 102 meters above the starting point. If the trip took 480 seconds, what was the minimum power required? 1. 5.0 × 104 W 2. 1.0 × 105 W 3. 1.2 × 1010 W 4. 2.3 × 1010 W 20. A 110-kilogram bodybuilder and his 55-kilogram 26. A joule is equivalent to a friend run up identical flights of stairs. The body- 1. N∙m builder reaches the top in 4.0 seconds while his 2. N∙s friend takes 2.0 seconds. Compared to the power 3. N/m developed by the bodybuilder while running up the 4. N/s stairs, the power developed by his friend is 1. the same 27. What is the power output of an electric motor that 2. twice as much lifts a 2.0-kilogram block 15 meters vertically in 6.0 3. half as much seconds? 4. four times as much 1. 5.0 J 2. 5.0 W 21. Which quantity is a vector? 3. 49 J 1. impulse 4. 49 W 2. power 3. speed WEP.A1, WEP.A2 Page 81 4. time APlusPhysics: WEP-Work and Power
Name: Period: WEP-Work and Power Base your answers to questions 28 and 29 on the information and diagram below. A 10-kilogram block is pushed across a floor by a horizontal force of 50 newtons. The block moves from point A to point B in 3.0 seconds. 28. Using a scale of 1.0 centimeter = 1.0 meter, determine the magnitude of the displacement of the block as it moves from point A to point B. 29. Calculate the power required to move the block from point A to point B in 3.0 seconds. [Show all work, includ- ing the equation and substitution with units.] 30. How much work is required to lift a 10-newton 33. A 60-kilogram student climbs a ladder a vertical weight from 4.0 meters to 40 meters above the sur- distance of 4.0 meters in 8.0 seconds. Approximately face of Earth? how much total work is done against gravity by the 1. 2.5 J student during the climb? 2. 3.6 J 1. 2.4 × 103 J 3. 3.6 × 102 J 2. 2.9 × 102 J 4. 4.0 × 102 J 3. 2.4 × 102 J 4. 3.0 × 101 J 31. Student A lifts a 50-newton box from the floor to a height of 0.40 meter in 2.0 seconds. Student B 34. A box is pushed to the right with a varying horizon- lifts a 40-newton box from the floor to a height of tal force. The graph below represents the relation- 0.50 meter in 1.0 second. Compared to student A, ship between the applied force and the distance the student B does box moves. 1. the same work but develops more power 2. the same work but develops less power 3. more work but develops less power 4. less work but develops more power 32. The graph below represents the relationship between the work done by a person and time. Identify the physical quantity represented by the What is the total work done in moving the box 6.0 slope of the graph. meters? 1. 9.0 J Page 82 WEP.A1, WEP.A2 2. 18 J 3. 27 J 4. 36 J APlusPhysics: WEP-Work and Power
Name: Period: WEP-Work and Power 35. The total work done in lifting a typical high school 41. Which quantity has both a magnitude and direction? physics textbook a vertical distance of 0.10 meter is 1. energy approximately 2. impulse 1. 0.15 J 3. power 2. 1.5 J 4. work 3. 15 J 4. 150 J 42. Two elevators, A and B, move at constant speed. Elevator B moves with twice the speed of elevator 36. Through what vertical distance is a 50-newton ob- A. Elevator B weighs twice as much as elevator A. ject moved if 250 joules of work is done against the Compared to the power needed to lift elevator A, gravitational field of Earth? the power needed to lift elevator B is 1. 2.5 m 1. the same 2. 5.0 m 2. twice as great 3. 9.8 m 3. half as great 4. 25 m 4. four times as great 37. A small electric motor is used to lift a 0.50-kilogram 43. What is the maximum height to which a motor mass at constant speed. If the mass is lifted a verti- having a power rating of 20.4 watts can lift a cal distance of 1.5 meters in 5.0 seconds, the average 5.00-kilogram stone vertically in 10 seconds? power developed by the motor is 1. 0.0416 m 1. 0.15 W 2. 0.408 m 2. 1.5 W 3. 4.16 m 3. 3.8 W 4. 40.8 m 4. 7.5 W 44. If a motor lifts a 400-kilogram mass a vertical 38. What is the maximum amount of work that a 6000- distance of 10 meters in 8.0 seconds, the minimum watt motor can do in 10 seconds? power generated by the motor is 1. 6.0 × 101 J 1. 3.2 × 102 W 2. 6.0 × 102 J 2. 5.0 × 102 W 3. 6.0 × 103 J 3. 4.9 × 103 W 4. 6.0 × 104 J 4. 3.2 × 104 W 39. How much work is done by the force lifting a 45. The graph below represents the work done against 0.1-kilogram hamburger vertically upward at con- gravity by a student as she walks up a flight of stairs stant velocity 0.3 meter from a table? at constant speed. 1. 0.03 J 2. 0.1 J 3. 0.3 J 4. 0.4 J 40. The watt∙second is a unit of Compared to the power generated by the student 1. power after 2.0 seconds, the power generated by the student 2. energy after 4.0 seconds is 3. potential difference 1. the same 4. electric field strength 2. twice as great 3. half as great APlusPhysics: WEP-Work and Power 4. four times as great WEP.A1, WEP.A2 Page 83
Name: Period: WEP-Work and Power 46. Which graph best represents the greatest amount of 50. An electric motor has a rating of 4.0 × 102 watts. work? How much time will it take for this motor to lift a 50-kilogram mass a vertical distance of 8.0 meters? 47. Calculate the average power required to lift a [Assume 100% efficiency.] 490-newton object a vertical distance of 2.0 meters 1. 0.98 s in 10 seconds. [Show all work, including the equa- 2. 9.8 s tion and substitution with units.] 3. 98 s 4. 980 s 51. Calculate the minimum power output of an electric motor that lifts a 1.30 × 104-newton elevator car vertically upward at a constant speed of 1.50 meters per second. [Show all work, including the equation and substitution with units.] 48. Which combination of fundamental units can be used to express the amount of work done on an object? 1. kg∙m/s 2. kg∙m/s2 3. kg∙m2/s2 4. kg∙m2/s3 49. The graph below represents the relationship between the force exerted on an elevator and the distance the elevator is lifted. How much total work is done by the force in lifting the elvator from 0.0 m to 9.0 m? 1. 9.0 × 104 J 2. 1.2 × 105 J 3. 1.5 × 105 J 4. 1.8 × 105 J Page 84 WEP.A1, WEP.A2 APlusPhysics: WEP-Work and Power
Name: Period: WEP-Springs Base your answers to questions 1 through 3 on the information and data table below. In an experiment, a student applied various forces to a spring and measured the spring’s corresponding elongation. The table below shows his data. 1. On the grid at right, plot the data points for force ver- sus elongation. 2. Draw the best-fit line 3. Using your graph, calculate the spring constant of the spring. [Show all work, including the equation and substitution with units.] 4. A 10-newton force is required to hold a stretched Base your answers to questions 7 and 8 on the informa- spring 0.20 meter from its rest position. What is the tion and graph below. potential energy stored in the stretched spring? 1. 1.0 J The graph represents the relationship between the force 2. 2.0 J applied to each of two springs, A and B, and their elonga- 3. 5.0 J tions. 4. 50 J 5. A 5-newton force causes a spring to stretch 0.2 meter. 7. What physical quantity is represented by the slope of What is the potential energy stored in the stretched each line? spring? 1. 1 J 8. A 1.0-kilogram mass is suspended from each spring. 2. 0.5 J If each mass is at rest, how does the potential energy 3. 0.2 J stored in spring A compare to the potential energy 4. 0.1 J stored in spring B? 6. The spring of a toy car is wound by pushing the car backward with an average force of 15 newtons through a distance of 0.50 meter. How much elastic potential energy is stored in the car’s spring during this process? 1. 1.9 J 2. 7.5 J 3. 30 J 4. 56 J APlusPhysics: WEP-Springs WEP..C1 Page 85
Name: Period: WEP-Springs 9. A spring scale reads 20 newtons as it pulls a 5.0-ki- 13. A spring with a spring constant of 80 newtons per logram mass across a table. What is the magnitude meter is displaced 0.30 meter from its equilibrium of the force exerted by the mass on the spring scale? position. The potential energy stored in the spring is 1. 49 N 1. 3.6 J 2. 20 N 2. 7.2 J 3. 5.0 N 3. 12 J 4. 4.0 N 4. 24 J Base your answers to questions 10 through 12 on the 14. The diagram below shows a 0.1-kilogram apple at- information and diagram below. tached to a branch of a tree 2 meters above a spring on the ground below. A mass, M, is hung from a spring and reaches equilib- rium at position B. The mass is then raised to position A and released. The mass oscillates between positions A and C. [Neglect friction.] The apple falls and hits the spring, compressing it 0.1 meter from its rest position. If all of the gravi- tational potential energy of the apple on the tree is transferred to the spring when it is compressed, what is the spring constant of this spring? 1. 10 N/m 2. 40 N/m 3. 100 N/m 4. 400 N/m 10. At which position, A, B, or C, is mass M located when 15. The graph below shows elongation as a function of the kinetic energy of the system is at a maximum? the applied force for two springs, A and B. Explain your choice. 11. At which position, A, B, or C, is mass M located when the gravitational potential energy of the system is at a maximum? Explain your choice. 12. At which position, A, B, or C, is mass M located when the elastic potential energy of the system is at a maximum? Explain your choice. Page 86 WEP.C1 Compared to the spring constant for spring A, the spring constant for spring B is 1. smaller 2. larger 3. the same APlusPhysics: WEP-Springs
Name: Period: WEP-Springs 16. As shown in the diagram below, a 0.50-meter-long spring is stretched from its equilibrium position to a length of 1.00 meter by a weight. If 15 joules of energy are stored in the stretched spring, what is the value of the spring constant? 1. 30 N/m 2. 60 N/m 3. 120 N/m 4. 240 N/m Base your answers to questions 17 through 19 on the information and data table below. A student performed an experiment in which the weight attached to a suspended spring was varied and the resulting total length of the spring measured. The data for the experiment are in the table below. Using the information in the data table, WEP..C1 Page 87 construct a graph on the grid at right by following the directions below. 17. Plot the data points for the attached weight versus total spring length. 18. Draw the line or curve of best fit. 19. Using your graph, determine the length of the spring before any weight was attached. APlusPhysics: WEP-Springs
Name: Period: WEP-Springs Base your answers to questions 20 and 21 on the infor- 23. The diagram below represents a spring hanging ver- mation and diagram below. tically that stretches 0.075 meter when a 5.0-newton block is attached. The spring-block system is at rest A pop-up toy has a mass of 0.020 kilogram and a spring in the position shown. constant of 150 newtons per meter. A force is applied to the toy to compress the spring 0.050 meter. 20. Calculate the potential energy stored in the com- The value of the spring constant is pressed spring. [Show all work, including the equa- 1. 38 N/m tion and substitution with units.] 2. 67 N/m 3. 130 N/m 21. The toy is activated and all the compressed spring’s 4. 650 N/m potential energy is converted to gravitational po- tential energy. Calculate the maximum vertical 24. A spring with a spring constant of 4.0 newtons height to which the toy is propelled. [Show all work, per meter is compressed by a force of 1.2 newtons. including the equation and substitution with units.] What is the total elastic potential energy stored in this compressed spring? 22. A 10-newton force compresses a spring 0.25 meter 1. 0.18 J from its equilibrium position. Calculate the spring 2. 0.36 J constant of this spring. [Show all work, including the 3. 0.60 J equation and substitution with units.] 4. 4.8 J 25. The spring in a scale in the produce department of a supermarket stretches 0.025 meter when a watermel- on weighing 1.0×102 newtons is placed on the scale. The spring constant for this spring is 1. 3.2 × 105 N/m 2. 4.0 × 103 N/m 3. 2.5 N/m 4. 3.1 × 10-2 N/m 26. When a 1.53-kilogram mass is placed on a spring with a spring constant of 30.0 newtons per meter, the spring is compressed 0.500 meter. How much energy is stored in the spring? 1. 3.75 J 2. 7.50 J 3. 15.0 J 4. 30.0 J Page 88 WEP.C1 APlusPhysics: WEP-Springs
Name: Period: WEP-Springs Base your answers to questions 27 through 30 on the information and data table below. The spring in a dart launcher has a spring constant of 140 newtons per meter. The launcher has six power settings, 0 through 5, with each successive setting having a spring compression 0.020 meter beyond the previous setting. Dur- ing testing, the launcher is aligned to the vertical, the spring is compressed, and a dart is fired upward. The maximum vertical displacement of the dart in each test trial is measured. The results of the testing are shown in the table below. Directions (27-28): Using the information in the data table, construct a graph on the grid below. 27. Plot the data points for the dart’s maximum vertical displacement versus spring compression. 28. Draw the line or curve of best fit. 29. Using information from your graph, calculate the en- ergy provided by the compressed spring that causes the dart to achieve a maximum vertical displacement of 3.50 meters. [Show all work, including the equa- tion and substitution with units.] 30. Determine the magnitude of the force, in newtons, needed to compress the spring 0.040 meter. APlusPhysics: WEP-Springs WEP..C1 Page 89
Name: Period: WEP-Springs Base your answers to questions 31 and 32 on the informa- 33. When a mass is placed on a spring with a spring tion below. constant of 15 newtons per meter, the spring is com- pressed 0.25 meter. How much elastic potential en- In a laboratory investigation, a student applied various ergy is stored in the spring? downward forces to a verticle spring. The applied forces 1. 0.47 J and the corresponding elongations of the spring from its 2. 0.94 J equilibrium position are recorded in the data table below. 3. 1.9 J 4. 3.8 J 31. Construct a graph on the grid below. Mark an ap- 34. The potential energy stored in a compressed spring propriate scale on the axis labeled “Force (N),” plot is to the change in the spring’s length as the kinetic the data points for force versus elongation, and draw energy of a moving body is to the body’s the best-fit line or curve. 1. speed 2. mass 3. radius 4. acceleration 35. The diagram below shows a toy cart possessing 16 joules of kinetic energy traveling on a frictionless, horizontal surface toward a horizontal spring. If the cart comes to rest after compressing the spring a distance of 1.0 meter, what is the spring constant of the spring? 1. 32 N/m 2. 16 N/m 3. 8.0 N/m 4. 4.0 N/m 36. A spring in a toy car is compressed a distance, x. When released, the spring returns to its original length, transferring its energy to the car. Conse- quently, the car having mass m moves with speed v. 32. Using your graph, calculate the spring constant of this Derive the spring constant, k, of the car’s spring in spring. [Show all work, including the equation and terms of m, x, and v. [Assume an ideal mechanical substitution with units.] system with no loss of energy.] Page 90 WEP.C1 APlusPhysics: WEP-Springs
Name: Period: WEP-Springs 37. The graph below represents the relationship between 40. Which graph best represents the relationship between the force applied to a spring and spring elongation for the elastic potential energy stored in a spring and its four different springs. elongation from equilibrium? Which spring has the greatest spring constant? 1. A 2. B 3. C 4. D Base your answers to questions 38 and 39 on the informa- 41. A child does 0.20 joule of work to compress the tion below. spring in a pop-up toy. If the mass of the toy is 0.010 kilogram, what is the maximum vertical height that A vertically hung spring has a spring constant of 150 the toy can reach after the spring is released? newtons per meter. A 2.00-kilogram mass is suspended 1. 20 m from the spring and allowed to come to rest. 2. 2.0 m 3. 0.20 m 38. Calculate the elongation of the spring produced by 4. 0.020 m the suspended 2.00-kilogram mass. [Show all work, including the equation and substitution with units.] 42. A vertical spring 0.100 meter long is elongated to a length of 0.119 meter when a 1.00-kilogram mass is attached to the bottom of the spring. The spring constant of this spring is 1. 9.8 N/m 2. 82 N/m 3. 98 N/m 4. 520 N/m 39. Calculate the total elastic potential energy stored in 43. An unstretched spring has a length of 10 centime- the spring due to the suspended 2.00-kilogram mass. ters. When the spring is stretched by a force of 16 [Show all work, including the equation and substitu- newtons, its length is increased to 18 centimeters. tion with units.] What is the spring constant of this spring? 1. 0.89 N/cm 2. 2.0 N/cm 3. 1.6 N/cm 4. 1.8 N/cm 44. When a spring is compressed 2.50 × 10-2 meter from its equilibrium position, the total potential energy stored in the spring is 1.25 × 10-2 joule. Calculate the spring constant of the spring. APlusPhysics: WEP-Springs WEP..C1 Page 91
Name: Period: WEP-Springs Base your answers to questions 45 and 46 on the information below. A student produced various elongations of a spring by applying a series of forces to the spring. The graph at right represents the relationship between the applied force and the elongation of the spring. 45. Determine the spring constant of the spring. 46. Calculate the energy stored in the spring when the elongation is 0.30 meter. [Show all work, including the equation and substitution with units.] 47. A spring gains 2.34 joules of elastic potential energy as it is compressed 0.250 meter from its equilibrium position. What is the spring constant of this spring? 1. 9.36 N/m 2. 18.7 N/m 3. 37.4 N/m 4. 74.9 N/m 48. A vertical spring has a spring constant of 100 new- tons per meter. When an object is attached to the bottom of the spring, the spring changes from its unstretched length of 0.50 meter to a length of 0.65 meter. The magnitude of the weight of the attached object is 1. 1.1 N 2. 15 N 3. 50 N 4. 65 N Page 92 WEP.C1 APlusPhysics: WEP-Springs
Name: Period: WEP-Energy 1. A 1-kilogram rock is dropped from a cliff 90 meters 7. A 45-kilogram boy is riding a 15-kilogram bicycle high. After falling 20 meters, the kinetic energy of with a speed of 8 meters per second. What is the the rock is approximately combined kinetic energy of the boy and the bicycle? 1. 20 J 1. 240 J 2. 200 J 2. 480 J 3. 700 J 3. 1440 J 4. 900 J 4. 1920 J 2. If the speed of a car is doubled, the kinetic energy of 8. The work done in moving a block across a rough the car is surface and the heat energy gained by the block can 1. quadrupled both be measured in 2. quartered 1. watts 3. doubled 2. degrees 4. halved 3. newtons 4. joules 3. A constant force is used to keep a block sliding at constant velocity along a rough horizontal track. As Base your answers to questions 9 through 11 on the the block slides, there could be an increase in its information below. 1. gravitational potential energy, only 2. internal energy, only A 50-kilogram child running at 6 meters per second 3. gravitational potential energy and kinetic energy jumps onto a stationary 10-kilogram sled. The sled is on 4. internal energy and kinetic energy a level frictionless surface. 4. As an object falls freely, the kinetic energy of the 9. Calculate the speed of the sled with the child after object she jumps onto the sled. [Show all work, including 1. decreases the equation and substitution with units.] 2. increases 3. remains the same 5. An object weighing 15 newtons is lifted from the 10. Calculate the kinetic energy of the sled with the ground to a height of 0.22 meter. The increase in child after she jumps onto the sled. [Show all work, the object’s gravitational potential energy is approxi- including the equation and substitution with units.] mately 1. 310 J 2. 32 J 3. 3.3 J 4. 0.34 J 6. A 0.50-kilogram ball is thrown vertically upward 11. After a short time, the moving sled with the child with an initial kinetic energy of 25 joules. Ap- aboard reaches a rough level surface that exerts a proximately how high will the ball rise? [Neglect air constant frictional force of 54 newtons on the sled. resistance.] How much work must be done by friction to bring 1. 2.6 m the sled with the child to a stop? 2. 5.1 m 3. 13 m 4. 25 m APlusPhysics: WEP-Energy WEP.B1, WEP.B2 Page 93
Name: Period: WEP-Energy 12. Which graph best represents the relationship between the kinetic energy, KE, and the velocity of an objct ac- celerating in a straight line? 13. The graph below represents the kinetic energy, gravitational potential energy, and total mechanical energy of a moving block. Which best describes the motion of the block? 1. accelerating on a flat horizontal surface 2. sliding up a frictionless incline 3. falling freely 4. being lifted at constant velocity Base your answers to questions 14 through 16 on the information and diagram below. A 1000-kilogram empty cart moving with a speed of 6 meters per second is about to collide with a stationary loaded cart having a total mass of 5000 kilograms, as shown. After the collision, the carts lock and move together. [Assume friction is negligible.] 14. Calculate the speed of the combined carts after the collision. [Show all work, including the equation and substi- tution with units.] 15. Calculate the kinetic energy of the combined carts after the collision. [Show all work, including the equation and substitution with units.] 16. How does the kinetic energy of the combined carts after the collision compare to the kinetic energy of the carts before the collision? Page 94 WEP.B1, WEP.B2 APlusPhysics: WEP-Energy
Name: Period: WEP-Energy 17. When a force moves an object over a rough, hori- 22. A 60-kilogram runner has 1920 joules of kinetic zontal surface at a constant velocity, the work done energy. At what speed is she running? against friction produces an increase in the object’s 1. 5.66 m/s 1. weight 2. 8.00 m/s 2. momentum 3. 32.0 m/s 3. potential energy 4. 64.0 m/s 4. internal energy 23. As a block slides across a table, its speed decreases Base your answers to questions 18 through 21 on the while its temperature increases. Which two changes information below. occur in the block’s energy as it slides? 1. a decrease in kinetic energy and an increase in The driver of a car made an emergency stop on a straight internal energy horizontal road. The wheels locked and the car skidded 2. an increase in kinetic energy and a decrease in to a stop. The marks made by the rubber tires on the dry internal energy asphalt are 16 meters long, and the car’s mass is 1200 3. a decrease in both kinetic energy and internal kilograms. energy 4. an increase in both kinetic energy and internal 18. Determine the weight of the car energy 19. Calculate the magnitude of the frictional force the 24. If the direction of a moving car changes and its road applied to the car in stopping it. [Show all speed remains constant, which quantity must remain work, including the equation and substitution with the same? units.] 1. velocity 2. momentum 3. displacement 4. kinetic energy 20. Calculate the work done by the frictional force in 25. What is the gravitational potential energy stopping the car. [Show all work, including the equa- with respect to the surface of the water tion and substitution with units.] of a 75.0-kilogram diver located 3.00 meters above the water? 1. 2.17×104 J 2. 2.21×103 J 3. 2.25×102 J 4. 2.29×101 J 26. As a ball falls freely (without friction) toward the ground, its total mechanical energy 1. decreases 2. increases 3. remains the same 21. Assuming that energy is conserved, calculate the 27. The gravitational potential energy, with respect to speed of the car before the brakes were applied. Earth, this is possessed by an object is dependent on [Show all work, including the equation and substitu- the object’s tion with units.] 1. acceleration 2. momentum APlusPhysics: WEP-Energy 3. position 4. speed WEP.B1, WEP.B2 Page 95
Name: Period: WEP-Energy Base your answers to questions 28 and 29 on the infor- 31. As shown in the diagram below, a student exerts an mation below. average force of 600 newtons on a rope to lift a 50-ki- logram crate a vertical distance of 3 meters. A boy pushes his wagon at constant speed along a level sidewalk. The graph below represents the relationship between the horizontal force exerted by the boy and the distance the wagon moves. 28. What is the total work done by the boy in pushing the Compared to the work done by the student, the wagon 4.0 meters? gravitational potential energy gained by the crate is 1. 5.0 J 1. exactly the same 2. 7.5 J 2. 330 J less 3. 120 J 3. 330 J more 4. 180 J 4. 150 J more 32. A book sliding across a horizontal tabletop slows until it comes to rest. Describe what change, if any, occurs in the book’s kinetic energy and internal energy as it slows. 29. As the boy pushes the wagon, what happens to the 33. A pendulum is pulled to the side and released from wagon’s energy? rest. Which graph best represents the relationship 1. Gravitational potential energy increases. between the gravitational potential energy of the 2. Gravitational potential energy decreases. pendulum and its displacement from its point of 3. Internal energy increases. release? 4. Internal energy decreases. 30. A 1.0-kilogram book resting on the ground is moved 1.0 meter at various angles relative to the horizontal. In which direction does the 1.0-meter displacement produce the greatest increase in the book’s gravita- tional potential energy? Page 96 WEP.B1, WEP.B2 APlusPhysics: WEP-Energy
Name: Period: WEP-Energy Base your answers to questions 34 through 36 on the information and diagram below. A 250-kilogram car is initially at rest at point A on a roller coaster track. The car carries a 75-kilogram passenger and is 20 meters above the ground at point A. [Neglect friction.] 34. Calculate the total gravitational potential energy, relative to the ground, of the car and the passenger at point A. [Show all work, including the equation and substitution with units.] 35. Calculate the speed of the car and passenger at point B. [Show all work, including the equation and substitution with units.] 36. Compare the total mechanical energy of the car and passenger at points A, B, and C. 37. Which graph best represents the relationship between the gravitational potential energy of an object near the sur- face of Earth and its height above Earth’s surface? 38. A horizontal force of 5.0 newtons acts on a 3.0-ki- 39. As a ball falls freely toward the ground, its total me- logram mass over a distance of 6.0 meters along a chanical energy horizontal, frictionless surface. What is the change in 1. decreases kinetic energy of the mass during its movement over 2. increases the 6.0-meter distance? 3. remains the same 1. 6.0 J 2. 15 J 3. 30 J 4. 90 J APlusPhysics: WEP-Energy WEP.B1, WEP.B2 Page 97
Name: Period: WEP-Energy Base your answers to questions 40 through 42 on the in- 44. A 1.00-kilogram ball is dropped from the top of a formation below. building. Just before striking the ground, the ball’s speed is 12.0 meters per second. What was the ball’s A roller coaster car has a mass of 290 kilograms. Starting gravitational potential energy, relative to the ground, from rest, the car acquires 3.13 × 105 joules of kinetic en- at the instant it was dropped? [Neglect friction.] ergy as it descends to the bottom of a hill in 5.3 seconds. 1. 6.00 J 2. 24.0 J 40. Calculate the height of the hill. [Neglect friction. 3. 72.0 J Show all work, including the equation and substitu- 4. 144 J tion with units.] 45. A person weighing 6.0 × 102 newtons rides an eleva- 41. Calculate the speed of the roller coaster car at the bot- tor upward at an average speed of 3.0 meters per sec- tom of the hill. [Show all work, including the equa- ond for 5.0 seconds. How much does this person’s tion and substitution with units.] gravitational potential energy increase as a result of this ride? 1. 3.6 × 102 J 2. 1.8 × 103 J 3. 3.0 × 103 J 4. 9.0 × 103 J 42. Calculate the magnitude of the average acceleration 46. Which combination of fundamental units can be used of the roller coaster car as it descends to the bottom to express energy? of the hill. [Show all work, including the equation and 1. kg∙m/s substitution with units.] 2. kg∙m2/s 3. kg∙m/s2 4. kg∙m2/s2 47. A ball is dropped from the top of a cliff. Which graph best represents the relationship between the ball’s total energy and elapsed time as the ball falls to the ground? [Neglect friction.] 43. The table below lists the mass and speed of each of four objects. Which two objects have the same kinetic energy? 1. A and D 2. B and D 3. A and C 4. B and C Page 98 WEP.B1, WEP.B2 APlusPhysics: WEP-Energy
Name: Period: WEP-Energy Base your answers to questions 48 through 50 on the information and diagram below. A 3.0-kilogram object is placed on a frictionless track at point A and released from rest. (Assume the gravitational potential energy of the system to be zero at point C.) 48. Calculate the gravitational potential energy of the object at point A. [Show all work, including the equation and substitution with units.] 49. Calculate the kinetic energy of the object at point B. [Show all work, including the equation and substitution with units.] 50. Which letter represents the farthest point on the track that the object will reach? 51. An object is thrown vertically upward. Which pair of graphs best represents the object’s kinetic energy and gravitational potential energy as functions of displacement while it rises? APlusPhysics: WEP-Energy WEP.B1, WEP.B2 Page 99
Name: Period: WEP-Energy Base your answers to questions 52 through 55 on the graph below, which represents the relationship between vertical height and gravitational potential energy for an object near Earth’s surface. 52. Based on the graph, what is the gravitational potential energy of the object when it is 2.25 meters above the surface of Earth? 53. Using the graph, calculate the mass of the object. [Show all work, including the equation and substitution with units.] 54. What physical quantity does the slope of the graph represent? 55. Using a straightedge, draw a line on the graph to represent the relationship between gravitational potential energy and vertical height for an object having a greater mass. 56. An object falls freely near Earth’s surface. Which graph best represents the relationship between the object’s ki- netic energy and its time of fall? Page 100 WEP.B1, WEP.B2 APlusPhysics: WEP-Energy