# Homework Help: Help on Uniform Circular Motion Problem Please!

1. Oct 1, 2007

### sam.

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

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

Derive a formula for the bullet speed v in terms of D, T, and a measured angle between the position of the hole in the first disk and that of the hole in the second. If required, use $$\pi$$, not its numeric equivalent. Both of the holes lie at the same radial distance from the shaft. $$\theta$$ measures the angular displacement between the two holes; for instance, $$\theta$$=0 means that the holes are in a line and means that when one hole is up, the other is down. Assume that the bullet must travel through the set of disks within a single revolution.

A diagram of this can be found here: http://ca.geocities.com/canbball/MRB_rr_8_a.jpg [Broken]

2. Relevant equations

Okay so I know that v=D/t
And that v = (2$$\pi$$r)/T

3. The attempt at a solution

I know that the disks rotate by 2 in time T. What I don't understand is how to express this in terms of $$\theta$$.

Any help would be greatly appreciated!

Last edited by a moderator: May 3, 2017
2. Oct 2, 2007

### TVP45

Can you state the angular velocity, omega, in terms of the angle theta?

In step 3, you've dropped a pi.