Four particles, each of mass M, are equally spaced on a circle of radius R and move under their mutual gravitational attraction. Find the speed of each particle.

Options

• Option A

  $\frac{GM}{R}$

• Option B

  $\sqrt{\left\lbrack\frac{2\sqrt2GM}{R}\right\rbrack}$

• Option C

  $\sqrt{\left\lbrack\frac{GM}{R}\left(2\sqrt2+1\right)\right\rbrack}$

• Option D

  $\sqrt{\left\lbrack\frac{GM}{R}\frac{\left(2\sqrt2+1\right)}{4}\right\rbrack}$