At which point would a skateboarder have the most kinetic energy?

1. At rest at the top of a half-pipe, just before gliding down the ramp.
2. At the very bottom of the half-pipe, after gliding down.
3. On his way back up the far side of the half-pipe
4. His kinetic energy would be the same everywhere

The difference between work and power is that:

1. An object must move for work to be done, but not for power to be exerted Work is always larger than power
2. Time is not important to determine the work done, but it is for the power exerted
3. They are exactly the same thing

What is FALSE about the binder(972 g) and the calculator(241 g) sitting on your desk?

1. Both have the same amount of gravitational potential energy.
2. Both have the same amount of kinetic energy.
3. If they fall off the desk, both will hit the floor at the same speed.
4. B and C are both False

Melika used 686 N of force to hold her body in the bottom of a push-up position 25 cm above the ground, for 30 seconds. How much work did Melika do?

1. 5.7 J
2. 170 J
3. 17000 J
4. None

5. Which unit below is NOT a possible unit for power?

1. W
2. Nm/s
3. J/min
4. N/s

6.In which of the following cases is work NOT being done?

A)	holding a watermelon at chest height
B)	pushing a bicycle 0.2 km [E]
C)	walking down a flight of stairs
D)	playing a guitar solo
E)	coasting to a stop on ice skates

7.Which of the following is NOT an expression for energy?

A)

B)

C)

D)

E)

8.Two boys have the same mass and are riding on identical bicycles. One boy has a speed of

8 m/s and the other a speed of 2 m/s. What is the ratio of the first boy's kinetic energy to the second boy's kinetic energy?

A)

16:1

B)

8:1

C)

4:1

D)

2:1

E)

1:1

9. A force F acting on a stationary block on a smooth level surface moves the block a horizontal displacement d in a time t. The power is

A)		C)	zero	E)
B)		D)

he sum of an object's gravitational potential energy and kinetic energy is called its

A)

conserved energy

B)

stored energy

C)

total mechanical energy

D)

thermal energy

11.Which of the following is equal to 1 joule (1 J)?

A)

1 N/kg

B)

1 N m

C)

1 N/s

D)

1 W/s

12.In which case is negative work being done?

A)	forward force is applied to a forward moving soccer ball to increase its speed in that direction.
B)	The work done by the Earth on a ball as the ball, initially at rest, falls 3.0 m down towards the Earth.
C)	The work done by the friction to slow a sled as it slides along the snow.
D)	A cart is moving at a constant velocity of 5.7 m/s [N] when a 0.5 N [downward] force is applied.

13. The energy "lost" pushing a box across a rough surface is transformed mostly into

A)

friction

B)

kinetic energy

C)

potential energy

D)

thermal energy

14.The speed of an object is doubled. The kinetic energy is

A)

the same

B)

half ()

C)

double ()

D)

quadruple ()

15.Which of the following is NOT an expression for energy?

A)

B)

C)

D)

E)

A 6.0kg object moving at 12.0m/s at a height of 3.0m above the ground has a kinetic energy of

A)

432.0 J

B)

176.6 J

C)

608.6 J

D)

255.4 J

E)

72.0 J

17. A 1400W motor uses 21kJ of energy to give a car 16kJ of kinetic energy. The efficiency of the motor is

A)

24%

B)

31%

C)

76%

D)

131%

E)

69%

18. The engine of a truck moving at 11.0m/s exerts 2100N of force. The power output of the engine is

A)

23.1 kW

B)

190.9 kW

C)

23.1 W

D)

231.0 W

E)

2111.0 W