s_3x03 Page 1 Physics Samples

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1 Physics Samples KE, PE, Springs 1. A 1.0-kilogram rubber ball traveling east at 4.0 meters per second hits a wall and bounces back toward the west at 2.0 meters per second. Compared to the kinetic energy of the ball before it hits the wall, the kinetic energy of the ball after it bounces off the wall is Name Per Date 5. The diagram below shows block A, having mass 2m and speed v, and block B having mass m and speed 2v. (A) one-fourth as great (B) one-half as great (C) the same (D) four times as great 2. The kinetic energy of a 980-kilogram race car traveling at 90. meters per second is approximately (A) J (C) J (B) J (D) J 3. An object moving at a constant speed of 25 meters per second possesses 450 joules of kinetic energy. What is the object s mass? (A) 0.72 kg (C) 18 kg (B) 1.4 kg (D) 36 kg Compared to the kinetic energy of block A, the kinetic energy of block B is (A) the same (C) one-half as great (B) twice as great (D) four times as great 6. Which graph best represents the relationship between gravitational potential energy (PE) and height (h) above the ground for an object near the surface of Earth? (A) (C) 4. Which graph best represents the relationship between the kinetic energy of a moving object and its velocity? (A) (C) (B) (D) (B) (D) 7. A girl rides an escalator that moves her upward at constant speed. As the girl rises, how do her gravitational potential energy and kinetic energy change? (A) Gravitational potential energy decreases and kinetic energy decreases. (B) Gravitational potential energy decreases and kinetic energy remains the same. (C) Gravitational potential energy increases and kinetic energy decreases. (D) Gravitational potential energy increases and kinetic energy remains the same. s_3x03 Page 1

2 8. Base your answer to the following question on the diagram below which shows a 1-kilogram mass and a 2-kilogram mass being dropped from a building 100 meters high. 11. A box weighing 1.0 x 10 2 Newtons is dragged to the top of an incline, as shown in the diagram below. The potential energy at the top of the building is (A) greater for the 1-kilogram mass (B) greater for the 2-kilogram mass (C) the same for both masses 9. A cart weighing 10 Newtons is pushed 10 meters on a level surface by a force of 5 Newtons. What is the increase in its potential energy? (A) 1 joule (C) 100 joules (B) 50 joules (D) 0 joules The gravitational potential energy of the box at the top of the incline is approximately (A) 1.0 x 10 2 J (C) 8.0 x 10 2 J (B) 6.0 x 10 2 J (D) 1.0 x 10 3 J 12. In the diagram below, an average force of 20. Newtons is used to pull back the string of a bow 0.60 meter. 10. A mass resting on a shelf 10.0 meters above the floor has a gravitational potential energy of 980. joules with respect to the floor. The mass is moved to a shelf 8.00 meters above the floor. What is the new gravitational potential energy of the mass? (A) 960. J (C) 490. J (B) 784 J (D) 196 J As the arrow, leaves the bow, its kinetic energy is (A) 3.4 J (C) 12 J (B) 6.0 J (D) 33 J 13. A 10.-kilogram mass falls freely a distance of 6.0 meters near the Earth's surface. The total kinetic energy gained by the mass as it falls is approximately (A) 60. J (C) 720 J (B) 590 J (D) 1,200 J s_3x03 Page 2

3 14. A force is applied to a block, causing it to accelerate along a horizontal, frictionless surface. The energy gained by the block is equal to the (A) work done on the block (B) power applied to the block (C) impulse applied to the block (D) momentum given to the block 18. The diagram below shows a cart at four positions as it moves along a frictionless track. At which positions is the sum of the potential energy and kinetic energy of the cart the same? 15. A 0.10-kilogram ball dropped vertically from a height of 1.0 meter above the floor bounces back to a height of 0.80 meter. The mechanical energy lost by the ball as it bounces is approximately (A) J (C) 0.30 J (B) 0.20 J (D) 0.78 J 16. The diagram below 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.] (A) A and B, only (B) B and C, only (C) C and D, only (D) all positions, A through D 19. The diagram below which represents a swinging pendulum. (A) 4.91 J (B) 50.0 J (C) 250. J (D) 491 J 17. The diagram below shows three positions, A, B, and C, in the swing of a pendulum, released from rest at point A. [Neglect friction.] The potential energy that an ideal pendulum has at point x equals the value of its kinetic energy at point (A) A (C) C (B) B (D) D Which statement is true about this swinging pendulum? (A) The potential energy at A equals the kinetic energy at C. (B) The speed of the pendulum at A equals the speed of the pendulum at B. (C) The potential energy at B equals the potential energy at C. (D) The potential energy at A equals the kinetic energy at B. s_3x03 Page 3

4 Base your answers to questions 20 and 21 on the diagram below which shows a 1-kilogram stone being dropped from a bridge 100 meters above a gorge. 23. As the object slides down the incline, the sum of the gravitational potential energy and kinetic energy of the object will (A) decrease (C) remain the same (B) increase 24. Base your answer to the following question on the diagram below which represents a block with initial velocity v 1 sliding along a frictionless track from point A through point E. 20. What will be the kinetic energy of the stone after it has fallen 50 meters? (A) 98 J (C) 50 J (B) 490 J (D) 100 J 21. As the stone falls, the gravitational potential energy of the stone (A) decreases (C) remains the same (B) increases Base your answers to questions 22 and 23 on the diagram below. The diagram represents a 1.00 kilogram object being held at rest on a frictionless incline. The velocity of the block will be least at point (A) A (C) C (B) B (D) E 25. A catapult with a spring constant of 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 takeoff is approximately (A) J (C) J (B) J (D) J 26. As a spring is stretched, its elastic potential energy (A) decreases (C) remains the same (B) increases 22. The object is released and slides the length of the incline. When it reaches the bottom of the incline, the object's kinetic energy will be closest to (A) 19.6 J (C) 9.81 J (B) 2.00 J (D) 4.00 J 27. A 3.0-kilogram mass is attached to a spring having a spring constant of 30. newtons per meter. The mass is pulled 0.20 meter from the spring's equilibrium position and released. What is the maximum kinetic energy achieved by the mass spring system? (A) 2.4 J (C) 1.2 J (B) 1.5 J (D) 0.60 J s_3x03 Page 4

5 28. A spring of negligible mass has a spring constant of 50. newtons per meter. If the spring is stretched 0.40 meter from its equilibrium position, how much potential energy is stored in the spring? (A) 20. J (C) 8.0 J (B) 10. J (D) 4.0 J Base your answers to questions 29 and 30 on the information below and on your knowledge of physics. Using a spring toy like the one shown in the diagram, a physics teacher pushes on the toy, compressing the spring, causing the suction cup to stick to the base of the toy. When the teacher removes her hand, the toy pops straight up and just brushes against the ceiling. She does this demonstration five times, always with the same result. When the teacher repeats the demonstration for the sixth time the toy crashes against the ceiling with considerable force. The students notice that in this trial, the spring and toy separated from the base at the moment the spring released. The teacher puts the toy back together, repeats the demonstration and the toy once again just brushes against the ceiling. 29. Describe the conversions that take place between pairs of the three forms of mechanical energy, beginning with the work done by the teacher on the toy and ending with the form(s) of energy possessed by the toy as it hits the ceiling. [Neglect friction.] 30. Explain, in terms of mass and energy, why the spring toy hits the ceiling in the sixth trial and not in the other trials. s_3x03 Page 5

6 Base your answers to questions 31 through 34 on the information and table below. The table lists the kinetic energy of a 4.0-kilogram mass as it travels in a straight line for 12.0 seconds. 31. Compare the speed of the mass at 6.0 seconds to the speed of the mass at 10.0 seconds. 32. Mark an appropriate scale on the axis labeled Kinetic Energy (J). 33. Plot the data points for kinetic energy versus time. 34. Calculate the speed of the mass at 10.0 seconds. [Show all work, including the equation and substitution with units.] s_3x03 Page 6

7 35. Base your answer to the following question on the information and diagram below. A 160.-newton box sits on a 10.-meter-long frictionless plane inclined at an angle of 30. to the horizontal as shown. Force (F) applied to a rope attached to the box causes the box to move with a constant speed up the incline. Calculate the amount of work done in moving the box from the bottom to the top of the inclined plane. [Show all work, including the equation and substitution with units.] s_3x03 Page 7

8 Base your answers to questions 36 and 37 on the information and diagram below. A block of mass m starts from rest at height h on a frictionless incline. The block slides down the incline across a frictionless level surface and comes to rest by compressing a spring through distance x, as shown in the diagram below. 36. Name the forms of mechanical energy possessed by the system when the block is in position A and in position B. 37. Determine the spring constant, k, in terms of g, h, m, and x. [Show all work including formulas and an algebraic solution for k.] s_3x03 Page 8