My first step was to calculate Torques acting on system, I found 3, one given(external):
a)torque produced by point mass:
(m2)grcos(θ)=(m2)gr
b)torque produced by spring
krsin(θ)rcos(θ)=kr2θ
c)external torque
τ_o(t)=10sin(20t)
I also calculated moments of inertia
I=m1r2+(1/2)m1∗r2
then I...