Jε=mgr

The angular acceleration ε = mgr = mgr/(Mr 2/2+Mr 2) = 2g/(3r), which is uniform angular acceleration.

Using the formula in the same form as linear uniform acceleration, the angular velocity when rotating α angle is obtained:

ω= √( 2εα)= √( 2 * 2gα/(3r))= 2√(gα/3r)