Download Chapter 6: Energy and Oscillations

Chapter 6: Energy and Oscillations
1. Which of the following is not an energy unit?
A. N·m
B. Joule
C. calorie
D. watt
E. kWh
2. Work is not being done on an object unless the
A. net force on the object is zero.
B. object is being accelerated.
C. speed is constant.
D. object is moving.
3. A wooden block slides down a rough incline. Which of the following statements is true?
A. The kinetic energy of the block is decreasing.
B. The gravitational potential energy of the block is increasing.
C. The mechanical energy of the block is constant.
D. The mechanical energy of the block is increasing.
E. The mechanical energy of the block is decreasing.
4. Virgil rides a skateboard (combined mass 100 kg) at 4 m/s, and Jill rides a bicycle (combined
mass 64 kg) at 5 m/s.
A. Virgil has the greater kinetic energy.
B. Virgil and Jill have equal kinetic energies.
C. Jill has the greater kinetic energy.
5. An object with a kinetic energy of 50 J is stopped in a distance of 0.01 m. The average force
that stops the object is
A. 0.5 N.
B. 50 N.
C. 500 N.
D. 5,000 N.
E. 50,000 N.
6. For a 0.1-kg frog to jump to a height of 1.0 meter requires an energy of about
A. 0.1 Joule.
B. 0.5 Joule.
C. 1.0 Joule.
D. 10 Joule.
7. A box is moved 10 m across a smooth floor by a force making a downward angle with the
floor, so that there is effectively a 10 N force acting parallel to the floor in the direction of
motion and a 5 N force acting perpendicular to the floor. The work done is
A. 150 J.
B. 100 J.
C. 50 J.
D. 10 J.
E. 5.0 J.
8. A box is pushed across a rough horizontal floor by a force acting parallel to the floor in the
direction of motion. A force doing negative work on the body is
A. gravity.
B. friction.
C. the applied force.
D. normal reaction force of floor upward on body.
E. a fictitious force.
9. A box is pushed across a rough horizontal floor by a force acting parallel to the floor in the
direction of motion. A force doing no work during the motion is
A. gravity.
B. friction.
C. the applied force.
10. The kinetic energy of a body is correctly given by which of the following expressions?
A. mv.
B. 2mv2.
C. mv2.
D. (½)mv2.
E. (½)mv.
11. Which of the following is not a unit of power?
A. watt
B. kilowatt
C. kilowatt-hour
D. joule/second
E. horsepower
12. If the speed of a car is doubled, the work to stop the car changes by a factor of
A. 4.
B. 2.
C. 1.
D. ½.
E. ¼.
13. A painter of mass 80 kg climbs 3.0 m up a ladder. The painter’s potential energy has
increased by
A. 240 J.
B. 261 J.
C. 784 J.
D. 1284 J.
E. 2352 J.
14. The potential energy of a spring of constant k that has been stretched a distance x is given by
A. kx.
B. (½)kx.
C. kx2.
D. (½)kx2.
E. (½)k/x.
15. A pendulum swings through 10 cycles in 5 seconds. The frequency of the pendulum is
A. 10 Hz.
B. 5 Hz.
C. 2 Hz.
D. 0.5 Hz.
E. 0.1 Hz.
Answers: D D E B D C B B A D C A E D C