Dynamics Review with Answers PDF

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1. Which statement about the movement of an object with zero acceleration is true? (1) The object must be at rest. (2) The object must be slowing down. (3) The object may be speeding up. (4) The object may be in motion. 2. A rocket in space can travel without engine power at constant speed in the same direction. This condition is best explained by the concept of (1) gravitation (3) acceleration (2) action-reaction (4) inertia 3. If the mass of a moving object could be doubled, the inertia of the object would be (1) halved (3) unchanged (2) doubled (4) quadrupled 4. A copper coin resting on a piece of cardboard is placed on a beaker as shown in the diagram below. When the cardboard is rapidly removed, the coin drops into the beaker.

The two properties of the coin which best explain its fall are its weight and its (1) temperature (3) volume (2) electrical resistance (4) inertia 5. A "push or pull" best describes the term (1) work (3) potential energy (2) momentum (4) force 6. Compared to 8 kilograms of feathers, 6 kilograms of lead has (1) less mass and less inertia (2) less mass and more inertia (3) more mass and less inertia (4) more mass and more inertia

7. Two forces are applied to a 2.0-kilogram block on a frictionless horizontal surface, as shown in the diagram below.

The acceleration of the block is (1) 1.5 m/s2 to the right (2) 2.5 m/s2 to the left (3) 2.5 m/s2 to the right (4) 4.0 m/s2 to the left 8. What is an essential characteristic of an object in equilibrium? (1) zero velocity (2) zero acceleration (3) zero potential energy (4) zero kinetic energy 9. A man standing on a scale in an elevator notices that the scale reads 30 newtons greater than his normal weight. Which type of movement of the elevator could cause this greater-than-normal reading? (1) accelerating upward (2) accelerating downward (3) moving upward at constant speed (4) moving downward at constant speed 10. Which object has the greatest inertia? (1) a 1.0-kilogram object moving at 15 meters per second (2) a 5.0-kilogram object at rest (3) a 10.-kilogram object moving at 2.0 meters per second (4) a 15-kilogram object at rest 11. If the mass of an object were doubled, its weight would be (1) halved (3) quadrupled (2) doubled (4) unchanged

12. Which graph best represents the motion of an object that is not in equilibrium as it travels along a straight line?

(1)

(3)

(2)

(4)

13. In the diagram below, a 10.-kilogram block is at rest on a plane inclined at 15° to the horizontal.

16. Base your answer to the following question on the graph below, which shows the velocity of a 1,500-kilogram car during a 20-second-time interval.

No unbalanced force is acting on the car during time interval (1) BC (3) EF (2) CD (4) FG 17. Which graph best represents the motion of a moving object with no unbalanced force acting on it?

As the angle of the incline is increased to 30.°, the mass of the block will (1) decrease (3) remain the same (2) increase 14. As a constant unbalanced force acts on an object in the direction of motion, the object's speed (1) decreases (3) remains the same (2) increases 15. A 1-kilogram object rests on a horizontal table top. The force that the table top exerts on the object is (1) 1 N (3) 0 N (2) 2 N (4) 9.8 N

(1)

(3)

(2)

(4)

18. A man weighing 800 Newtons is standing in an elevator. If the elevator rises with an acceleration of 9.8 meters per second2, the force exerted by the elevator on the man will be (1) 400 N (3) 1600 N (2) 800 N (4) 2000 N

22. An unbalanced force of 10 Newtons acts on a 20kilogram mass for 5 seconds. The acceleration of the mass is (1) 0.5 m/s2 (2) 2 m/s2 (3) 40 m/s2 (4) 200 m/s2

19. The graph represents the net force acting on an object as a function of time. During which time interval is the velocity of the object constant?

(1) 0 to 2 (2) 2 to 3

(3) 3 to 4 (4) 4 to 5

20. Which two graphs represent the motion of an object on which the net force is zero? (1)

23. An object with a mass of 0.5 kilogram starts from rest and achieves a maximum speed of 20 meters per second in 0.01 second. What average unbalanced force accelerates this object? (1) 1,000 N (3) 0.1 N (2) 10 N (4) 0.001 N 24. In the graph below, the acceleration of an object is plotted against the unbalanced force on the object.

(2)

(3)

(4)

21. A force of F Newtons gives an object with a mass of M an acceleration of A. The same force F will give a second object with a mass of 2M an acceleration of (1) A/2 (3) A (2) 2A (4) A/4

What is the object's mass? (1) 1 kg (3) 0.5 kg (2) 2 kg (4) 0.2 kg 25. A student weighing 500. Newtons stands on a spring scale in an elevator. If the scale reads 520. Newtons, the elevator must be (1) accelerating upward (2) accelerating downward (3) moving upward at constant speed (4) moving downward at constant speed 26. Net force F causes mass m1 to accelerate at rate a. A net force of 3F causes mass m2 to accelerate at rate 2a. What is the ratio of mass m1 to mass m 2? (1) 1:3 (3) 1:2 (2) 2:3 (4) 1:6

27. Two forces are applied to a 2.0-kilogram block on a frictionless horizontal surface, as shown in the diagram below.

The acceleration of the block is (1) 5.0 m/s2 to the right (2) 5.0 m/s2 to the left (3) 3.0 m/s2 to the right (4) 3.0 m/s2 to the left 28. A net force of 10. Newtons accelerates an object at 5.0 meters per second2. What net force would be required to accelerate the same object at 1.0 meter per second2? (1) 1.0 N (3) 5.0 N (2) 2.0 N (4) 50. N 29. A 2.0-kilogram body is initially traveling at a velocity of 40. meters per second east. If a constant force of 10. newtons due east is applied to the body for 5.0 seconds, the final speed of the body is (1) 15 m/s (3) 65 m/s (2) 25 m/s (4) 130 m/s 30. In the diagram below, a box is on a frictionless horizontal surface with forces F1 and F2 acting shown.

If the magnitude of F1 is greater than the magnitude of F2 , then the box is (1) moving at constant speed in the direction of F1 (2) moving at constant speed in the direction of F2 (3) accelerating in the direction of F1 (4) accelerating in the direction of F2

31. A 1.0-kilogram block is placed on each of four frictionless planes inclined at different angles. On which inclined plane will the acceleration of the block be greatest? (1)

(2)

(3)

(4)

32. A bat applies an average force of 500 Newtons on a baseball for 0.20 second. What was the average force applied by the ball on the bat? (1) 100 N (3) 500 N (2) 200 N (4) 1,000 N 33. A baseball bat moving at high velocity strikes a feather. If air resistance is neglected, compared to the force exerted by the bat on the feather, the force exerted by the feather on the bat will be (1) smaller (3) the same (2) larger 34. If the magnitude of the gravitational force of Earth on the Moon is F, the magnitude of the gravitational force of the Moon on Earth is (1) smaller than F (3) equal to F (2) larger than F

35. A series of unbalanced forces was applied to each of two blocks, A and B. The graphs below show the relationship between unbalanced force and acceleration for each block.

Compared to the mass of block A, the mass of block B is (1) the same (2) twice as great (3) half as great 36. Which statement explains why a book resting on a table is in equilibrium? (1) There is a net force acting downward on the book. (2) The weight of the book equals the weight of the table. (3) The acceleration due to gravity is 9.8 m/s 2 for both the book and the table. (4) The weight of the book and the table's upward force on the book are equal in magnitude, but opposite in direction. 37. As shown in the diagram below, an inflated balloon released from rest moves horizontally with velocity v.

The velocity of the balloon is most likely caused by (1) action-reaction (2) centripetal force (3) gravitational attraction (4) rolling friction

(4) four times as great

38. A person kicks a 4.0-kilogram door with a 48newton force causing the door to accelerate at 12 meters per seconds. What is the magnitude of the force exerted by the door on the person? (1) 48 N (3) 12 N (2) 24 N (4) 4.0 N 39. A rocket engine thrusts the rocket into space because (1) the exhaust pushes against the ground (2) the exhaust pushes against the air (3) every action produces an equal and opposite reaction (4) matter and energy are conserved 40. A mosquito flying over a highway strikes the windshield of a moving truck. Compared to the magnitude of the force of the truck on the mosquito during the collision, the magnitude of the force of the mosquito on the truck is (1) smaller (3) the same (2) larger 41. A 50-kilogram student, standing on the Earth, attracts the Earth with a force closest to (1) 0 N (3) 50 N (2) 5 N (4) 500 N

42. If a 65-kilogram astronaut exerts a force with a magnitude of 50. newtons on a satellite that she is repairing, the magnitude of the force that the satellite exerts on her is (1) 0 N (2) 50. N less than her weight (3) 50. N more than her weight (4) 50. N

48. A 3.0-kilogram mass weighs 15 Newtons at a given point in the Earth's gravitational field. What is the magnitude of the acceleration due to the gravity at this point? (1) 45 m/s2 (2) 9.8 m/s2 (3) 5.0 m/s2 (4) 0.20 m/s2

43. A carpenter hits a nail with a hammer. Compared to the magnitude of the force the hammer exerts on the nail, the magnitude of the force the nail exerts on the hammer during contact is (1) less (3) the same (2) greater

49. On the planet Gamma, a 4.0-kilogram mass experiences a gravitational force of 24 Newtons. What is the acceleration due to gravity on planet Gamma? (1) 0.17 m/s2 (2) 6.0 m/s2 (3) 9.8 m/s2 (4) 96 m/s2

44. Base your answer to the following question on the information below: A 10.-kilogram object, starting from rest, slides down a frictionless incline with a constant acceleration of 2.0 m/sec 2 for four seconds. What is the approximate weight of the object? (1) 1 N (3) 100 N (2) 10 N (4) 1,000 N 45. As a satellite is accelerated away from the Earth by a rocket, the satellite's mass (1) decreases (3) remains the same (2) increases

50. A 2.0-kilogram mass weighs 10. Newtons on planet X. The acceleration due to gravity on planet X is approximately (1) 0.20 m/s2 (2) 5.0 m/s2 (3) 9.8 m/s2 (4) 20. m/s2 51. A 2.0-kilogram object is falling freely near Earth’s surface. What is the magnitude of the gravitational force that Earth exerts on the object? (1) 20. N (3) 0.20 N (2) 2.0 N (4) 0.0 N

46. What is the gravitational force of attraction between a planet and a 17-kilogram mass that is freely falling toward the surface of the planet at 8.8 meters per second2? (1) 150 N (3) 1.9 N (2) 8.8 N (4) 0.52 N

52. As an astronaut travels from the surface of Earth to a position that is four times as far away from the center of Earth, the astronaut’s (1) mass decreases (2) mass remains the same (3) weight increases (4) weight remains the same

47. A 60-kilogram skydiver is falling at a constant speed near the surface of Earth. The magnitude of the force of air friction acting on the skydiver is approximately (1) 0 N (3) 60 N (2) 6 N (4) 600 N

53. As more force is applied to a steel box sliding on a steel surface, the coefficent of kinetic friction will (1) decrease (3) remain the same (2) increase

54. A 60.-kilogram physics student would weigh 1560 newtons 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 55. At a given location on the earth's surface, which graph best represents the relationship between an object's mass (M) and weight (W) ?

58. The graph at the right shows the relationship between weight and mass for a series of objects. The slope of this graph represents (1) change of position (2) normal force (3) momentum (4) acceleration due to gravity 59. The graph below shows the relationship between weight and mass for a series of objects on the Moon.

(1)

(3)

(2)

(4)

56. Which graph best represents the relationship between the masses of different objects and the gravitational force acting on them as they fall freely near the Earth's surface?

(1)

(2)

(3)

(4)

57. Compared to the force needed to start sliding a crate across a rough level floor, the force needed to keep it sliding once it is moving is (1) less (3) the same (2) greater

The acceleration due to gravity on the Moon is approximately (1) 0.63 m/s2 (2) 1.6 m/s2 (3) 9.8 m/s2 (4) 32 m/s2 60. In order to keep an object weighing 20 Newtons moving at constant speed along a horizontal surface, a force of 10 Newtons is required. The force of friction between the surface and the object is (1) 0 N (3) 20 N (2) 10 N (4) 30 N

61. The diagram below represents a box shown sliding down an inclined plane. Toward which point will the force of friction on the box be directed?

(1) 1 (2) 2

(3) 3 (4) 4

62. Base your answer to the following question on the diagram below which represents a 3.0kilogram mass being moved at a constant speed by a force of 6.0 Newtons.

The magnitude of the force of friction acting on the mass is (1) 0 N (3) 3 N (2) 1.8 N (4) 6 N 63. A box initially at rest on a level floor is being acted upon by a variable horizontal force, as shown in the diagram at the right. Compared to the force required to start the box moving, the force required to keep it moving at constant speed is

(1) less (2) greater

(3) the same

64. If a 30-Newton force is required to accelerate a 2-kilogram object at 10 meters per second 2 , over a level floor, then the magnitude of the frictional force acting on the object is (1) 0 N (3) 20 N (2) 10 N (4) 30 N 65. A wooden block is at rest on a horizontal steel surface. If a 10.-Newton force applied parallel to the surface is required to set the block in motion, how much force is required to keep the block moving at constant velocity? (1) less than 10. N (3) 10. N (2) greater than 10. N 66. In the diagram below, surface B of the wooden block has the same texture as surface A, but twice the area of surface A

If force F is required to slide the block at constant speed across the table on surface A, approximately what force is required to slide the block at constant speed across the table on surface B? (1) F (3) ½F (2) 2F (4) 4F 67. Sand is often placed on an icy road because the sand (1) decreases the coefficient of friction between the tires of a car and the road (2) increases the coefficient of friction between the tires of a car and the road (3) decreases the gravitational force on a car (4) increases the normal force of a car on the road

68. Block A is pulled with constant velocity up an incline as shown in the diagram below.

Which arrow best represents the direction of the force of friction acting on block A?

(1)

(3)

(2)

(4)

71. Jill is pulling a 200. Newton sled through the snow at constant velocity using a horizontal force of 10. Newtons. What is the kinetic coefficient of friction of the sled on the snow? (1) 0.02 (3) 0.20 (2) 0.05 (4) 20 72. The force required to start an object sliding across a uniform horizontal surface is larger than the force required to keep the object sliding at a constant velocity. The magnitudes of the required forces are different in these situations because the force of kinetic friction (1) is greater than the force of static friction (2) is less than the force of static friction (3) increases as the speed of the object relative to the surface increases (4) decreases as the speed of the object relative to the surface increases 73. The table below lists the coefficients of kinetic friction for four materials sliding over steel.

69. The diagram below represents a block sliding down an incline.

Which vector best represents the frictional force acting on the block? (1) A (3) C (2) B (4) D 70. When a 12-newton horizontal force is applied to a box on a horizontal tabletop, the box remains at rest. The force of static friction acting on the box is (1) 0 N (2) between 0 N and 12 N (3) 12 N (4) greater than 12 N

A 10.-kilogram block of each of these materials is pulled horizontally across a steel floor at constant velocity. Which block requires the smallest applied force to keep it moving at constant velocity? (1) aluminum (3) copper (2) brass (4) steel

74. The diagram below shows a granite block being slid at constant speed across a horizontal concrete floor by a force parallel to the floor.

Which pair of quantities could be used to determine the coefficient of friction for the granite on the concrete? (1) mass and speed of the block (2) mass and normal force on the block (3) frictional force and speed of the block (4) frictional force and normal force on the block

75. The diagram below shows a 4.0-kilogram object accelerating at 10. meters per second2 on a rough horizontal surface.

What is the magnitude of the frictional force Ff acting on the object? (1) 5.0 N (2) 10. N (3) 20. N

(4) 40. N

Answer Key [New Exam] 1.

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