How to find work done by friction?

[Vee9]

Homework Statement

"In more than one way, find the loss of energy of the ball as it rolls down the ramp."

If for one method, I use W_{Non-conservative force} = Change in Energy, would the work be by kinetic friction?

If it is, then how would I find the work done by friction (which is the NCF) if I only have the following information:
http://i1097.photobucket.com/albums/g349/Physics_/Energy.jpg
Mass of ball = 0.0083 kg

Homework Equations

U_k = F_friction/ Normal
W_NCF = Change in energy
N = mg

The Attempt at a Solution

This is where I got stuck - I tried to find F_friction but I don't have U_k.

 

[kudoushinichi88]

you don't need to know the coefficient of friction. you just need to know how much work is done by the friction.

If you calculate the energy on top of the ramp and at the bottom, you will realize that some of the energy is gone. Where did it go to?

 

[Vee9]

you don't need to know the coefficient of friction. you just need to know how much work is done by the friction.

If you calculate the energy on top of the ramp and at the bottom, you will realize that some of the energy is gone. Where did it go to?

But if W_friction = F_friction (x) and I don't know the force of friction, how do I find it's work?

And it goes to friction, doesn't it? :O