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Energy Quiz

1-18-06

True or False

1.The units of work are the same as the units of energy.

2.Potential energy is energy due to the motion of an object.

3.Any moving object will keep moving until the energy in it runs out.

4.A body moving at 3 m/s has half the energy of the same object moving at 6 m/s.

5.Work is equal to the product of force and time.

6.A joule is equivalent to a newton·meter.

7.A weightlifter holding a 100-kg barbell over his head is doing twice as much work as a weightlifter holding a 50-kg barbell over his head.

8.Power is the rate at which energy is created.

9.Potential energy and kinetic energy are both forms of mechanical energy.

10.The unit of power is the watt.

Multiple choice:

11.The gravitational potential energy of a falling object is transformed into

a. power

b. weight

c. speed

d. kinetic energy

e. work

12.A 100-watt light bulb uses energy at the rate of

a. 100 joules per hour

b. 10 joules in ten seconds

c. 100 joules per second

d. 100 joules per minute

13.The gravitational potential energy of a 1-kg mass that is 3 meters from the floor is

a. 3 kg·m

b. 3 m/kg

c. 29.4 joules

d. 3 joules

14.The diagram represents a 20-N force pulling a 5-kg object up a hill at a constant rate of 2 meters per second. The kinetic energy of the moving object is

a. 50 J

b. 15 J

c. 10 J

d. 5 J

5kg10 m

20 N30 m

15.At what point in its fall does the kinetic energy of a freely falling object equal its potential energy?

a. at the start of the fall

b. at all points during the fall

c. halfway between the start and the end

d. at the end of the fall

16.A basketball player who weighs 600 N jumps 0.5 meters off the floor. What is her kinetic energy just before hitting the floor?

a. 600 J

b. 30 J

c. 300 J

d. 60 J

17.A force of 2 newtons drags a 2.5 N shoe across the floor at constant velocity for 2 meters. What is the work done against friction?

a. 4 J

b. 1 J

c. 0 J

d. 5 J

e. 10 J

Switch papers with someone. Count the number correct and write it at the top of the paper.

1. T

2. F

3. F

4. F

5. F

6. T

7. T

8. F

9. T

10. T

11. D

12. C

13. C

14. C

15. C

16. C

17. A