Problem 4.45

A uniform rod of mass $m=1.5$ kg suspended by two identical threads $l=90 \mathrm{~cm}$ in length (Fig. 4.13) was turned through a small angle about the vertical axis passing through its middle point C. The threads deviated in the process through an angle $\alpha=5.0^{\circ}$. Then the rod was released to start performing small oscillations. Find: (a) the oscillation period; (b) the rod's oscillation energy.