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

Explanation

In this case two particle maintain gravitational force of attraction diameterically. The gravitational force on one of the particle must be equal to the necessary centripetal force
`(mV^(2))//r=(Vmm)/((2r)^(2))impliesV=sqrt((Gm)/(4r))`