Homework Help: Conservation of Angular Momentum of solid sphere

1. Oct 26, 2009

G-reg

1. The problem statement, all variables and given/known data
A small solid sphere, with radius 0.25 cm and mass 0.61 g rolls without slipping on the inside of a large fixed hemisphere with radius 17 cm and a vertical axis of symmetry. The sphere starts at the top from rest.

And I figured out that the KE at the bottom is = .001J

2. Relevant equations
I really don't know what equations would be relevant besides a proportion..

3. The attempt at a solution
I'm thinking it's something like

(#/.001) = (x/100)
and I cross multiply to find x
but I really have no clue and would really appreciate some help on this one!

2. Oct 26, 2009

rock.freak667

What exactly do you want to find?

3. Oct 26, 2009

G-reg

The fraction of its kinetic energy at the bottom is associated with rotation about an axis through its center of mass

4. Oct 26, 2009

rock.freak667

How did you get the kinetic energy at the bottom?

5. Oct 26, 2009

G-reg

by multiplying mgh = (6.1e-4)(9.8)(.17) = .001J

6. Oct 26, 2009

rock.freak667

Then you are measuring potential energy relative to a plane passing through the radius of the hemisphere (taken as 0 potential energy).

In that case, the potential energy at the bottom is mgh = (6.1e-4)(9.8)(-0.17) = -0.001 J

Ok, so at the top, what energy does it have?

At the bottom what types of energy does the sphere possess?

7. Oct 26, 2009

G-reg

Ok, so at the top it would be 0?
At the bottom it would be all PE again