# Homework Help: Angular acceleration of a bar on a hinge

1. Jun 13, 2010

### mickellowery

1. The problem statement, all variables and given/known data
A bar on a hinge starts from rest and rotates with $$\alpha$$=(10+6t) rad/s2 t is in seconds. Determine the angle in radians the bar turns in the first 4 seconds.

2. Relevant equations
I'm a little stumped how to get this one started. I assume i need to get it from angular acceleration to angular displacement, but I'm not exactly sure how to do that. So do I have to integrate it with respect to time twice?

3. The attempt at a solution

2. Jun 13, 2010

### Chewy0087

That's right. Remember to use constants of integration/ boundary conditions in general (although it should make no difference in this case).