1, the initial power of gravity is perpendicular to the component of the rod =mgcos60, the moment arm is L/2, and the initial moment =mgL/4.

Moment of inertia/moment of inertia = angular acceleration when the moment of inertia of the rod at point O is known.

Angular acceleration =(mgL/4)/(mL squared/3) = 3g/(4l) = 0.75g/l.

2. Gravity potential energy = rotational kinetic energy

(1/2)(mL square /3)ω square =mg(L/2)sin60, and the solution is ω = root sign (3gsin60/L).