# Net torque! Need help with angular acceleration.

1. Dec 8, 2009

### zelli

1. The problem statement, all variables and given/known data
A certain wheel has a rotational inertia of 12 kg m2. As it turns through 5.0 rev its angular velocity increases from 5.0 rad/s to 6.0 rad/s. If the net torque is constant, its value is:

2. Relevant equations
Angular acceleration = dW/dT
Net torque = (angular acceleration)*(rotational inertia)
Θf = Θi + (Wi)(dT) + $$\frac{1}{2}$$ $$\alpha$$$$\Delta$$t2

3. The attempt at a solution
I am confused on how to find dT. The equations have have both have two unknowns (t & $$\alpha$$)

Last edited: Dec 8, 2009
2. Dec 8, 2009

### ApexOfDE

why dont you try this formula:

(wf)^2 - (w0)^2 = 2 alpha * omega.

3. Dec 10, 2009

### zelli

Thank you so much! That worked. I'm glad you had that equation. I did not, and it happened to be on the test.
!!