Physics - Circular Motion Question with Solution | TestHub

A particle of mass 5 kg is free to slide on a smooth ring of radius $\mathrm{r}=20\mathrm{cm}$ fixed in a vertical plane. The particle is attached to one end of a spring whose other end is fixed to the top point O of the ring. Initially the particle is at rest at a point A of the ring such that $\angle \mathrm{OCA}=60^{\circ },\mathrm{C}$ being the centre of the ring. The natural length of the spring is also equal to $r=20\mathrm{cm}$. After the particle is released and slides down the ring the contact force between the particle \& the ring becomes zero when it reaches the lowest position B . Determine the force constant of the spring.