AP Review: Work, Energy, & 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

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

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

• mgL

• mgh

While a person lifts a book of mass 2 kg from the floor to a tabletop, 1.5 m above the floor, how much work does the gravitational force do on the book?

• -30 J

• -15 J

• 0 J

• 15 J

A satellite is currently orbiting Earth in a circular orbit of radius R; its kinetic energy is K₁ . If the satellite is moved and enters a new circular orbit of radius 2R, what will be its kinetic energy?

An object of mass m is traveling at constant speed v in a circular path of radius r. How much work is done by the centripetal force during one-half of a revolution?

• 0

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

• mgh

• mgs - Fh

• mgh - Fs

• mgh - Fs

As a rock of mass 4 kg drops from the edge of a 40-meter high cliff, it experiences air resistance, whose average strength during the descent is 20 N. At what speed will the rock hit the ground?

• 10 m/s

• 12 m/s

• 16 m/s

• 20 m/s

An astronaut drops a rock from the op 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