Why does the Golf Ball Heat Up After Coming to Rest?

[cashflow]

Homework Statement

A golf ball is dropped onto hard ground and, after a few bounces, comes to rest.

Why is the golf ball’s temperature slightly higher after it comes to rest?

1. The ball acquired energy from friction
with the air molecules.

2. The air temperature is higher than that
of the ball.

3. Each collision with the ground gives a
small kinetic energy to the atoms in the ball.

Homework Equations

None

The Attempt at a Solution

I think it's 1 because friction heats up the ball and adds KE to the system. But when it collides with the ground doesn't that remove KE from the system? And air is a higher temperature than the ball too, right?

 

[Andrew Mason]

The answer is not 1. The friction does no work since the ball does not move against the (static) friction force. Every time the ball hits the ground, it compresses. That compression stores energy in the ball. But, since the ball eventually comes to rest, we know that some of that energy is not returned as ball kinetic energy. Where does it go?

AM

 

[cashflow]

Thanks. I understand why 3 is correct, but how does the ball not move against the static friction force? I mean I thought friction caused by air always a factor?

 

[Andrew Mason]

Thanks. I understand why 3 is correct, but how does the ball not move against the static friction force? I mean I thought friction caused by air always a factor?

I read the problem too quickly. I thought it was referring to friction with the ground. Sorry to confuse you!

The ball does not gain energy from the air. There is some loss of ball energy due to friction with air molecules. But it is not energy from the air transferring to the ball. It is the other way around. Furthermore, it would not increase the temperature of the ball perceptibly.

AM

 

[cashflow]

Thanks! That makes sense now.