Physics - Rotation Question with Solution | TestHub

In the diagram shown below, the rod is uniform having mass M and length L. When it is making an angle $\theta =60^{\circ }$, the rod is released from the state of rest (and spring in its natural length). The rod comes to state of rest when the angle $\theta$ reduces to 30°. What should be the initial compression in the spring (when $\theta =60^{\circ }$ ) so that the whole system can remain in the state of rest? (there is no friction between any surfaces)