ch7&amp;8

# ch7&amp;8 - Walker CHAPTER 7 Work and Kinetic Energy 1...

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Walker CHAPTER 7 Work and Kinetic Energy 1) The SI unit of work is expressed as A) watt. B) newton. C) newton/second. D) joule. Answer: D Diff: 1 Page Ref: Sec. 7-1 2) The work done by the centripetal force on an object with a mass of 1 kg moving with a constant velocity of 4 m/s into a circular path of radius 0.6 m for one full cycle is A) 100.7 J B) 3.8 J C) 0 J D) 80 J Answer: C Diff: 1 Page Ref: Sec. 7-1 3) A person carries a mass of 10 kg and walks along the + x -axis for a distance of 100m with a constant velocity of 2 m/s. What is the work done by this person? A) 0 J B) 20 J C) 200 J D) None of the other choices is correct. Answer: A Diff: 1 Page Ref: Sec. 7-1 Figure 7-1 4) An object of mass = 2 kg is pulled by a constant force F = 4 N for a horizontal distance of 2 m. (Refer to Figure 7-1.) What is the work done along the + x -axis? Neglect friction. A) 8 kg m/s 2 B) 8 kg m 2 /s 2 C) 7 kg m/s 2 D) 7 kg m 2 /s 2 Answer: D Diff: 2 Page Ref: Sec. 7-1 5) Work is expressed as the dot product of the applied force and displacement caused by that force. Answer: TRUE Diff: 1 Page Ref: Sec. 7-1 6) A person applies a constant force of 20 N to a rock of 1000 kg. For 20 seconds. What is the work done by this person if the rock does not move at all by this applied force? A) 1000 J B) 20,000 J C) 0 J D) 400 J Answer: C

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Diff: 1 Page Ref: Sec. 7-1 A constant force of 100 N is applied to a mass of 40.0 kg as shown in figure 7-2. The force causes a displacement of 20.0 m to this mass along the + x -axis. Neglect friction. Figure 7-2 7) What is the work done by the component of the force in Figure 7-2 along the + x -axis? A) 1530 N B) 1520 Nm C) 2000 N D) 2000 Nm Answer: B Diff: 2 Page Ref: Sec. 7-1 8) What is the work done by the component of the force in Figure 7-2 along the + y -axis? A) 1530 N B) 1530 Nm C) 0 Nm D) 2000 Nm Answer: C Diff: 2 Page Ref: Sec. 7-1 9) A 100 kg object is pulled vertically upwards by a constant force of 4000 N for a distance of 20.0 m. What is the work done by the net force on the object? A) 60,400 kg m/s 2 B) 80,000 kg m/s 2 C) 80,000 kg m 2 /s 2 D) 60,400 kg m 2 /s 2 Answer: D Diff: 2 Page Ref: Sec. 7-1 10) A 100 kg object is pulled vertically upwards by a constant force of 4000 N for a distance of 20.0 m. What is the work done by the applied force on the object? A) 60,400 kg m/s 2 B) 80,000 kg m/s 2 C) 80,000 kg m 2 /s 2 D) 60,400 kg m 2 /s 2 Answer: C Diff: 2 Page Ref: Sec. 7-1 11) A person lifts a mass of 20.0 kg vertically upwards at a constant speed of 0.200 m/s through a distance of 0.800 m. What is the work done by the person? A) 16.0 J B) 156 J C) 3.20 J D) None of the other choices is correct. Answer: B Diff: 1 Page Ref: Sec. 7-1 12) A person applies a constant force on an object of mass 20 kg that causes the object to move
horizontally at a constant speed of 0.20 m/s through a distance of 0.80 m. What is the work done on the object? A) 10 J

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ch7&amp;8 - Walker CHAPTER 7 Work and Kinetic Energy 1...

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