One end of a spring of natural length
Question:

One end of a spring of natural length $\mathrm{h}$ and spring constant $\mathrm{k}$ is fixed at the ground and the other is fitted with a smooth ring of mass $\mathrm{m}$ which is allowed to slide on a horizontal rod fixed at a height $h$ (figure 8-E13). Initially, the spring makes an angle of $37^{\circ}$ with the vertical when the system is released from rest. Find the speed of the ring when the spring becomes vertical.

Solution: