A uniform ring of mass m is lying at a distance `sqrt(3)` a from the centre of mass M just over the sphere (where a is the radius of the ring as well as that of the sphere). Find the magnitude of gravitational force between them .

Explanation

Net force on ring `= int_("whole ring") dF sin60^(@)`
`=int_("whole ring")(GM(dm))/((2a)^(2))(sqrt3)/(2)`
`=(sqrt3GMm)/(8a^(2))`
as `int_("whole ring") dm=m`