Question

Two particles of equal mass go round a circle of radius R under the action of their mutual gravitational attraction. The speed of each particle is

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

Both the particles moves diametrically opposite position along the circular path of radius R and the gravitational force provides required centripetal force

$\frac{m{v}^2}{R}=\frac{Gmm}{(2R{)}^2}\Rightarrow v=\frac{1}{2}\sqrt{\frac{Gm}{R}}$