# Angular momentum of a rotating disk

1. Oct 20, 2007

### aligass2004

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

What is the angular momentum of the 1.2kg, 3.6cm diameter rotating disk in the figure below?

http://i241.photobucket.com/albums/ff4/alg5045/ex13-47.gif

2. Relevant equations

3. The attempt at a solution

I tried using L = Iw. w = 600 rev/min x (1 min/60s) x 2*pi radians = 62.832. Then I found I = 1/2 m(r^2) = .019. Then L = 1.194, but it wasn't right.

2. Oct 20, 2007

### learningphysics

convert cm to m. looks like you made a mistake in the conversion. 1.8cm = 0.018m

Last edited: Oct 20, 2007
3. Oct 20, 2007

### aligass2004

Grrrr.....I thought I did. I did kinda. I did I = 1/2 (1.2) (.18^2)...instead of (.018). I got it.

4. Oct 20, 2007

### learningphysics

cool. yeah, just noticed the 0.18. When I first posted, I thought you left it as cm... but then I realized that that didn't make sense with the L you'd gotten...

I'll catch u later aligass2004. got to sleep.

5. Oct 20, 2007

Night! :)