# Homework Help: 2011 F = ma Contest Question # 25

1. Jan 23, 2012

### clesling

1. The problem statement, all variables and given/known data

A hollow cylinder with a very thin wall (like a toilet paper tube) and a block are placed at rest at the top of a plane with inclination  above the horizontal. The cylinder rolls down the plane without slipping and the block slides down the plane; it is found that both objects reach the bottom of the plane simultaneously. What is the coefficient of kinetic friction between the block and the plane?

2. Relevant equations

K = (1/2)MV^2 + (1/2)IW^2 for I = MR^2 and W = V/R

3. The attempt at a solution

I have tried many different approaches: F = ma as well as assuming the same mass and/or velocity at the end of the ramp, but have had no success. Thanks for your time and consideration!

2. Jan 23, 2012

### Staff: Mentor

Start by finding the acceleration of the rolling cylinder.

3. Jan 23, 2012

### clesling

Hey, thanks for the response! That really helped and I was able to figure this one out finally.