# Homework Help: Angular Momentum of plates

1. Dec 22, 2011

### max1546

1. The problem statement, all variables and given/known data
The bent plate has a mass of 70kg per square meter of surface area and revolves about the z-axis at the rate w=30rad/sec. Determine the angular momentum H of the plate about the z-axis. (Neglect the mass of the hub and the thickness of the plate)

http://img839.imageshack.us/img839/9853/angularmomentum.jpg [Broken]

2. Relevant equations
w=w k
HG=-Izzwzi-Izywzj+Izwzk

3. The attempt at a solution
Splitting the bodies into various parts and calculating. However, as it is about the axis, and not the point, confused.

Last edited by a moderator: May 5, 2017
2. Dec 22, 2011

### LawrenceC

You would use the parallel axis theorem to move the moments of inertia from centroidal points to the axis of rotation. Then determine the angular momentum.

3. Dec 22, 2011

### vela

Staff Emeritus
Show us what you actually did. It's hard to figure out what's confusing you if all you give us is a vague description of what you tried.