# Moment of inertia for ball rolling up a ramp.

1. Jul 20, 2012

### azurken

1. The problem statement, all variables and given/known data
A ball with mass 1.0 kg and radius 0.20m rolls without slipping along level ground with a speed of 10 m/s. The ball then rolls up an incline reaching a maximum vertical height of 8.0 m. What is the moment of inertia of the ball? (Do not assume the ball is a uniform sphere).

m=1.0kg
r=0.20m
v=10m/s

2. Relevant equations
I=(2/5)mr^2

3. The attempt at a solution
Since I really have no clue on where to start this one. I guess I'll focus in on that since it's not a uniform sphere I can still assume it's a ball and use the above formula to plug it in and solve it right?

It comes out to 0.016

2. Jul 20, 2012

### TSny

Re: Moment of inertia for balling rolling up a ramp.

No, the formula you stated is only valid for a uniform solid sphere. So, you can't assume the formula applies in this problem.

Think of a general important principle that you could use to solve this problem.

3. Jul 20, 2012

### azurken

Re: Moment of inertia for balling rolling up a ramp.

Conservation of energy?

4. Jul 20, 2012

### TSny

Re: Moment of inertia for balling rolling up a ramp.

Yes. Give it a try.