# Four particles of equal masses M move along a circle of radius R under the action of their mutual gravitational attraction….

Q: Four particles of equal masses m move along a circle of radius R under the action of their mutual gravitational attraction. The speed of each particle.

(a) $\displaystyle \frac{1}{2}\sqrt{(2\sqrt2 +1)\frac{Gm}{R}}$

(b) $\displaystyle \sqrt{(\sqrt2 +1)\frac{Gm}{R}}$

(c) $\displaystyle \sqrt{(2\sqrt2 +1)\frac{Gm}{R}}$

(d) $\displaystyle \frac{1}{2}\sqrt{(\sqrt2 +1)\frac{Gm}{R}}$

Ans: (a)