# Physics Practice Questions Exam 2 - Questions about Energy

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http://www.phys.uidaho.edu/documents/Practice%20Questions%20Exam%202.pdf?pid=89574&doc=1

### three times the usual power output

1. If you do work on an object in one-third the usual time, your power output is
A) one third the usual power output.
B) the usual power output.
C) three times the usual power output.
D) impossible to predict without additional information.

### 1 W

2. The power required to exert 1 N force, over a distance of 1 m in 1 second is
A) 1 W. B) 2 W. C) 1/3 W. D) 3 W. E) none of these.

### 2 W

3.Do 100 J of work in 50 s and your power output is
A) 1/2 W B) 2 W. C) 4 W. D) 50 W. E) 5,000 W.

### twice as much

4.If an object is raised twice as high, its potential energy will be
A) half as much
B) twice as much.
C) four times as much.
D) impossible to determine unless the time is given.

### twice as much

5. An object lifted 10 meters gains 200 J of potential energy. If the same object is lifted 20 meters, its potential energy gain is
A) half as much.
B) the same.
C) twice as much.
D) four times as much.
E) more than four times as much.

### twice as much work

6.A 1000-kg car and a 2000-kg car are hoisted the same distance. Raising the more massive car requires
A) less work.
B) as much work.
C) twice as much work.
D) four times as much work.
E) more than four times as much work.

### moving

7. An object that has kinetic energy must be
A) moving.
B) falling.
C) at an elevated position.
D) at rest.
E) none of these

### location

8. An object may have potential energy because of its
A) speed.
B) acceleration.
C) momentum.
D) location.
E) none of these

### decreased

9. When bullets are fired from an airplane in the forward direction, the momentum of the airplane will be
A) decreased.
B) unchanged.
C) increased.

### half as much

10. A clerk can lift containers a vertical distance of 1 meter or can roll them up a 2 meter-long ramp to the same elevation. With the ramp, the applied force required is about
A) half as much.
B) twice as much.
C) the same.
D) four times as much.

### 40 J

11.A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy that is
A) less than 40 J.
B) more than 40 J.
C) 40 J.
D) impossible to predict without additional information

### heat

12. When a car is braked to a stop, its kinetic energy is transformed to
A) stopping energy.
B) potential energy.
C) energy of motion.
D) energy of rest.
E) heat.

### always false

13. A hydraulic press, like an inclined plane, is capable of increasing energy.
A) sometimes true
B) always false
C) always true
D) sometimes false

### always true

14. A hydraulic press, like a wheel and axle, is capable of multiplying force input.
A) always true
B) always false
C) sometimes true
D) sometimes false

### the same as its potential energy

15.
After rolling halfway down an incline a marbleʹs kinetic energy is
A) less than its potential energy.
B) greater than its potential energy.
C) the same as its potential energy.
D) impossible to determine.

### the top

16. The ball rolling down an incline has its maximum potential energy at
A) the top.
B) a quarter of the way down.
C) halfway down.
D) the bottom.

### the bottom

17. A ball rolling down an incline has its maximum kinetic energy at
A) the top.
B) halfway down.
C) three-quarters of the way down.
D) the bottom.

### the bottom

18. A block of ice sliding down an incline has its maximum speed at
A) the top.
B) the bottom.
C) halfway down.
D) difficult to predict without knowing the slope of the incline
E) difficult to predict without knowing the coefficient of friction

### potential energy

19. Neglecting friction, a small ball and a similar large ball, at rest, are allowed to roll down an incline. for only one second. At this instant, the large ball will have a greater
A) potential energy.
B) kinetic energy.
C) speed.
D) all of the above
E) impossible to predict with the information given

### none of the above choices

20. A light aluminum ball and a heavy lead ball of the same size are allowed to roll down an incline. When they are halfway down the incline, they will have identical
A) kinetic energies.
B) potential energies.
C) momentum.
D) inertias.
E) none of the above choices

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