Net torque Need help with angular acceleration.

[zelli]

Homework Statement

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:

Homework Equations

Angular acceleration = dW/dT
Net torque = (angular acceleration)*(rotational inertia)
Θ_f = Θ_i + (W_i)(dT) + $$\frac{1}{2}$$ $$\alpha$$$$\Delta$$t²

The Attempt at a Solution

I have dW = 5-6=-1rad/s
I am confused on how to find dT. The equations have have both have two unknowns (t & $$\alpha$$)

 

[ApexOfDE]

why don't you try this formula:

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

 

[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.
!