# Three Disks Coupled by Two Belts

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

The figure below shows three rotating, uniform disks that are coupled by belts. One belt runs around the rims of disks A and C. Another belt runs around a central hub on disk A and the rim of disk B. The belts move smoothly without slippage on the rims and hub. Disk A has radius R; its hub has radius 0.6000R; disk B has radius 0.2000R; and disk C has radius 1.500R. Disks B and C have the same density (mass per unit volume) and thickness. What is the ratio of the magnitude of the angular momentum of disk C to that of disk B?

L(C)/L(B)=?

Image: http://ift.tt/1gyQ6zO

**2. Relevant equations**

L=mvr=Iw (w is angular speed)

I(disk)=(mr^2)/2

**3. The attempt at a solution**

Honestly I have no clue how to even start this…

I think that the density will somehow give me mass to plug into equation for I, which can then be plugged into L. But I don’t know how to get w or v and without those I don’t know how to get L.

http://ift.tt/1p1EWVn

## Leave a comment