Physics 6

An object may have potential energy because of its-

location.

If an object has kinetic energy, then it also must have-

momentum.

An object that has kinetic energy must be-

moving.

If you push for a half hour or a whole hour against a stationary wall-

no work on the wall is done in either case.

A woman carries a heavy box across a room at a constant speed. How much work does she do on the box while walking?

none.

A job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of-

power.

Which has greater kinetic energy, a car traveling at 30 km/hr or a car of half the mass traveling at 60 km/hr?

the 60 km/hr car.

If you do work on an object in one-third the usual time, your power output is-

three times the usual power output.

Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate-

twice as far as the slower arrow.

A 1000-kg car and a 2000-kg car are hoisted the same distance. Raising the more massive car requires-

twice as much work.

If you push an object a given distance, while applying twice the force, you do-

twice as much work.

If you push an object twice as far while applying the same force, you do-

twice as much work.

If an object is raised twice as high, its potential energy will be-

twice as much.

If you find that twice as much work is needed to perform a task but it takes twice as much time, the amount of power required is-

unchanged.

It takes 40 J to push a large box 4 m across a floor. Assuming the push is in the same direction as the move, what is the magnitude of the force on the box?

10 N.

A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has-

16 times the KE.

A car moving at 50 km/hr skids 20 m with locked brakes. How far will the car skid with locked brakes if it were traveling at 150 km/hr?

180 m.

Do 100 J of work in 50 s and your power output is-

2 W.

Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed to do this job was-

50 W.

A 2-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground?

80 J.