# Rotational Dynamics Problem

1. Oct 21, 2004

### ruck101

Here's the problem:

diameter = 3.45 cm
angular speed = 11.4 rad/s
angular deceleration = -.96 rad/s

How far does the coin roll before coming to a stop?

How would I set this problem up? Thanks!

2. Oct 21, 2004

### Pyrrhus

Remember

$$v = r \omega$$

$$a = r \alpha$$

3. Oct 21, 2004

### ruck101

thanks for the reply.
ok, I converted 3.45 cm to m = .0345 m
then, I got the linear velocity = 11.4 x .0345 = .3933 m/s
next, I got the linear acceleration = -.96 x .0345 = -.03312 m/s^2

ok, I plug all of this into a kinematics equation and get 5.94 m, does this sound right? Thanks!

4. Oct 21, 2004

### Spectre5

r is radius....you must change the diameter to radius

5. Oct 21, 2004

### ruck101

dang, I did that the first time I tried this..lol. ok let me reattempt this.

6. Oct 21, 2004

### ruck101

I get the same exact thing.

7. Oct 22, 2004

Anyone.....?