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Conservation of Energy Class: Name: 1. ___________ Date: The diagram shows a cart at four positions as it moves along its track. At which positions is the sum of the potential energy and kinetic energy of the cart the same? 3. As the pendulum swings from position A to position B as shown in the diagram, what is the relationship of kinetic energy to potential energy? [Neglect friction.] (1) The kinetic energy decrease is more than the potential energy increase. (1) A and B, only (2) The kinetic energy increase is more than the potential energy decrease. (2) B and C, only (3) The kinetic energy decrease is equal to the potential energy increase. (3) C and D, only (4) all positions, A through D 2. (4) The kinetic energy increase is equal to the potential energy decrease. As a pendulum moves from the bottom of its swing to the top of its swing, the 4. (2) kinetic energy of the pendulum remains the same An object 10 meters above the ground has Z joules of potential energy. If the object falls freely, how many joules of kinetic energy will it have gained when it is 5 meters above the ground? (3) potential energy of the pendulum decreases (1) Z (1) kinetic energy of the pendulum increases (4) potential energy of the pendulum increases page 1 (2) 2Z (3) Z 2 (4) 0 5. As an object falls freely near the Earth's surface, the loss in gravitational potential energy of the object is equal to its 8. A cart of mass M on a frictionless track starts from rest at the top of a hill having height h1 , as shown in the diagram. What is the kinetic energy of the cart when it reaches the top of the next hill, having height h2 ? (1) loss of height (2) loss of mass (3) gain in velocity (1) Mgh1 (4) gain in kinetic energy (2) Mg (h1 h2 ) (3) Mg (h2 h3 ) (4) 0 6. The diagram shown represents a frictionless track. A 10-kilogram block starts from rest at point A and slides along the track. 9. As the block moves from point A to point B, the total amount of gravitational potential energy changed to kinetic energy is approximately (1) 5 J (2) 20 J (3) 50 J (4) 500 J In the accompanying diagram, an average force of 20. newtons is used to pull back the string of a bow 0.60 meter. As the arrow leaves the bow, its kinetic energy is 7. What is the approximate potential energy of the block at point C ? (1) 20 J (2) 200 J (3) 300 J (4) 500 J Class: ___________ page 2 (1) 3.4 J (2) 6.0 J (3) 12 J (4) 33 J Conservation of Energy 10. The accompanying diagram shows a moving, 5.00-kilogram cart at the foot of a hill 10.0 meters high. For the cart to reach the top of the hill, what is the minimum kinetic energy of the cart in the position shown? [Neglect energy loss due to friction.] 12. A 55.0-kilogram diver falls freely from a diving platform that is 3.00 meters above the surface of the water in a pool. When she is 1.00 meter above the water, what are her gravitational potential energy and kinetic energy with respect to the water's surface? (1) PE = 1620 J and KE = 0 J (2) PE = 1080 J and KE = 540 J (1) 4.91 J (2) 50.0 J (3) PE = 810 J and KE = 810 J (3) 250. J (4) 491 J (4) PE = 540 J and KE = 1080 J 13. 11. A catapult with a spring constant of 1:0 104 newtons per meter is required to launch an airplane from the deck of an aircraft carrier. The plane is released when it has been displaced 0.50 meter from its equilibrium position by the catapult. The energy acquired by the airplane from the catapult during takeo is approximately (1) 1:3 103 J (2) 2:0 104 J (3) 2:5 103 J (4) 1:0 104 J Class: ___________ A block weighing 40. newtons is released from rest on an incline 8.0 meters above the horizontal, as shown in the diagram below. If 50. joules of heat is generated as the block slides down the incline, the maximum kinetic energy of the block at the bottom of the incline is page 3 (1) 50. J (2) 270 J (3) 320 J (4) 3100 J Conservation of Energy 14. The diagram below shows a toy cart possessing 16 joules of kinetic energy traveling on a frictionless, horizontal surface toward a horizontal spring. 15. A wooden crate is pushed at constant speed across a level wooden oor. Which graph best represents the relationship between the total mechanical energy of the crate and the duration of time the crate is pushed? (1) 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 (2) (3) (4) Class: ___________ page 4 Conservation of Energy 16. Base your answer(s) to the following question(s) on the information below. 17. 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. A wound spring provides the energy to propel a toy car across a level oor. At time ti , the car is moving at speed vi across the oor and the spring is unwinding, as shown below. At time tf , the spring has fully unwound and the car has coasted to a stop. Which statement best describes the-transformation of energy that occurs between times ti and tf ? (1) Gravitational potential energy at ti converted to internal energy at tf . As the boy pushes the wagon, what happens to the wagon's energy? (2) Elastic potential energy at ti is converted to kinetic energy at tf . (3) Both elastic potential energy and kinetic energy at ti are converted to internal energy at tf . (1) Gravitational potential energy increases. (2) Gravitational potential energy decreases. (4) Both kinetic energy and internal energy at ti are converted to elastic potential energy at tf . (3) Internal energy increases. (4) Internal energy decreases. Class: ___________ page 5 Conservation of Energy 18. A ball is dropped from the top of a cli . Which graph best represents the relationship between the ball's total energy and elapsed time as the ball falls to the ground? [Neglect friction.] 19. (1) A child, starting from rest at the top of a playground slide, reaches a speed of 7.0 meters per second at the bottom of the slide. What is the vertical height of the slide? [Neglect friction.] (1) 0.71 m (2) 1.4 m (3) 2.5 m (4) 3.5 m (2) (3) 20. (4) Which statement describes the kinetic energy and total mechanical energy of a block as it is pulled at constant speed up an incline? (1) Kinetic energy decreases and total mechanical energy increases. (2) Kinetic energy decreases and total mechanical energy remains the same. (3) Kinetic energy remains the same and total mechanical energy increases. (4) Kinetic energy remains the same and total mechanical energy remains the same. Class: ___________ page 6 Conservation of Energy Problem-Attic format version 4.4.183 c 2011–2013 EducAide Software _ Licensed for use by B Fejzo Terms of Use at www.problem-attic.com Class: ___________ 1. Answer: 4 2. Answer: 4 3. Answer: 4 4. Answer: 3 5. Answer: 4 6. Answer: 4 7. Answer: 2 8. Answer: 2 9. Answer: 3 10. Answer: 4 11. Answer: 1 12. Answer: 4 13. Answer: 2 14. Answer: 1 15. Answer: 1 16. Answer: 3 17. Answer: 3 18. Answer: 4 19. Answer: 3 20. Answer: 3 Conservation of Energy 06/27/2013