Momentum & Energy

A librarian carries a stack of books across the library at a constant speed. How much work does he do on the box while walking across the room?

• More information is needed about the distance walked

• More information is needed about the weight of the books.

• More information is needed about the weight of the books and the distance walked.

• None, the force applied and distance are not in the same direction.

Which task requires the most work: lifting a 10 kg sack 3 meters or lifting a 5 kg sack 5 meters?

• lifting the 10 kg sack

• lifting the 5 kg sack

• both require the same amount of work

• neither one require work

A teacher pushes a cart 6 meters. A second, identical cart is pushed 3 meters with the same force. The work done on the second cart will be ___ as the work done on the first cart.

• half as much

• twice as much

• four times as much

• the same amount

An object is pushed a given distance. A second object is pushed twice the distance with the same force. The work done on the second object is ____ as the work done on the first object.

• half as much

• twice as much

• four times as much

• the same amount

A woman walks up a flight of stairs. The gain in her gravitational potential energy is calculated. If she runs up the stairs at twice the speed, her gain in gravitational potential energy will be ____.

• 1/4

• 1/2

• same

• double

• 4 times larger

An object may have potential energy because of its ___.

• acceleration

• location

• speed

• momentum

Two blocks, one 3 times as heavy as the other, are dropped to the ground from the roof of a building. Just before hitting the ground, the heavier block has ___.

• as much kinetic energy as the lighter one

• 1/3 as much kinetic energy as the lighter one

• 3 times as much kinetic energy as the lighter one

• 9 times as much kinetic energy as the lighter one

• 1/9 as much kinetic energy as the lighter one

A book is about to fall off a shelf is an example of which one of the following?

• elastic potential energy

• chemical potential energy

• kinetic energy

• gravitational potential energy

Two identical trains are traveling along a track at different speeds. The faster train is going twice the speed of the slower train. The faster train has ___ the kinetic energy of the slower train.

• 1/4 of

• 1/2 of

• 2 times

• 4 times

Determine which one requires the most work by the brakes on a car.

• slowing down from 60 m/s to 50 m/s

• slowing down from 60 m/s to 0 m/s

• slowing down from 20 m/s to 12 m/s

• slowing down from 30 m/s to 10 m/s