A 10 kg solid disk of radius 0.50 m is rotated about an axis through its center. If the disk accelerates from rest to an angular speed of 3.0 rad/s while rotating 2.0 revolutions, what net torque is required?
2 revs = 2*6.28 rad = 12.56 rad
First calculate angular acceleration:
v^2 = v0^2 + ...
This solution is provided in 69 words. It uses revolutions to calculate radius, and then calculates angular acceleration and torque.