Unit 7 #3

A steel ball has 20 J of kinetic energy. If it rolls up a ramp with no friction, how much potential energy will it have when it stops rolling upward?

• 20 J

• 40 J

• 60 J

• There's no way to know

Answer explanation

Without friction, all the kinetic energy becomes potential energy.

A ball rolls down a ramp, onto some carpet and comes to a stop. What happened to the energy when it is stopped?

• It becomes potential energy

• It becomes external kinetic energy

• It becomes momentum

• It is lost to the surroundings

What is the total energy at the top (position A)?

• 10,000 J

• 7500 J

• 5000 J

• 2500 J

What is the external kinetic energy 1/4th of the way down (position B)?

• 10,000 J

• 7500 J

• 5000 J

• 2500 J

What is the gravitational potential energy half of the way down (position C)?

• 10,000 J

• 7500 J

• 5000 J

• 2500 J

What is the external kinetic energy 3/4th of the way down (position D)?

• 10,000 J

• 7500 J

• 5000 J

• 2500 J

As the diver fell, what happened to the energy?

• Gravitational PE became external KE and the total energy didn't change

• External KE became Gravitational PE and the total energy didn't change

• Gravitational PE became external KE and the total energy decreased

• External KE became Gravitational PE and the total energy increased

The ball rolls from position A , down the ramp to position D and then up to position G, all without any friction.

Which letter shows the ball when it has THE MOST potential energy?

• Position A

• Position B

• Position C

• Position F

• Position G

Answer explanation

PE = mgh

The height is the greatest at position A

The ball rolls from position A , down the ramp to position D and then up to position G, all without any friction.

Which letter shows the ball when it has NO potential energy?

• Position B

• Position C

• Position D

• Position E

• Position F

Answer explanation

PE = mgh

The height is the least at position D

The ball rolls from position A , down the ramp to position D and then up to position G, all without any friction.

Which letter shows the ball when it has THE MOST kinetic energy?

• Position B

• Position C

• Position D

• Position E

• Position F

Answer explanation

Since position D is the lowest, that is where the most gravitational PE has become external KE.