Q. Consider a nebula in the form of a ring of radius $R$ and mass $M$. A star of mass $m(m<< M)$ is located at distance $R$ from the centre of the ring on its axis, initially at rest. The speed with which it crosses the centre of the ring is $v=\sqrt{(p-\sqrt{q}) \frac{G M}{R}} .$ Find $(p+q) .$
Gravitation
Solution: