The Princeton Review Chapter 7 Work, Energy, and Power

A force F of strength 20 N acts on an object of mass 3 kg as it moves a distance of 4 m. If F is perpendicular to the 4 m displacement, the work it does is equal to

• 0 J

• 60 J

• 80 J

• 600 J

• 2,400 J

Under the influence of a force, an object of mass 4 kg accelerates from 3 m/s to 6 m/s in 8 s. How much work was done on the object during this time?

• 27 J

• 54 J

• 72 J

• 96 J

• Cannot be determined from the information given

A box of mass m slides down a frictionless inclined plane of length L and vertical height h. What is the change in its gravitational potential energy?

A 4 kg box is pulled up a ramp of angle theta = 30º and height = 5 m at a constant velocity. How much work is done by the normal force?

• 160 J

• 80 J

• 40 J

• 20 J

• 0 J

A man stands in an elevator as it begins to ascend. Does the normal force from the floor do work on the man?

• Yes, and the work done will be positive.

• Yes, and the work done will be negative.

• Yes, but the sign can't be determined.

• No, the normal force will do no work in any situation.

• No, the normal force will do no work in this situation, but it can in others.

A block of mass 3.5 kg slides down a frictionless inclined plane of length 6.4 m that makes an angle of 30º with the horizontal. If the block is released from rest at the top of the incline, what is its speed at the bottom?

• 5.0 m/s

• 5.7 m/s

• 6.4 m/s

• 8.0 m/s

• 10 m/s

A block of mass m slides from rest down an inclined plane of length s and height h. If F is the magnitude of the force of kinetic friction acting on the block as it slides, then the kinetic energy of the block when it reaches the bottom of the incline will be equal to

If a 1,000 kg car is accelerating at a rate of 4 m/s^2 and experiencing 300 N of drag force, how much force do the engines have to produce? Ignore any frictional effects with the road.

• 16,300 N

• 15,700 N

• 4,300 N

• 4,000 N

• 3,700 N

An astronaut drops a rock from the top of a crater on the Moon. When the rock is halfway down to the bottom of the crater, its speed is what fraction of its final impact speed?

A force of 200 N is required to keep an object sliding at a constant speed of 2 m/s across a rough floor. How much power is being expended to maintain this motion?

• 50 W

• 100 W

• 200 W

• 400 W

• Cannot be determined from the information given