A uniform ring of mas m and radius a is placed directly above a uniform sphere of mass M and of equal radius. The centre of the ring is at a distance `sqrt3` a from the centre of the sphere. Find the gravitational force exerted by the sphere on the ring.

Options

A. `(sqrt(3)GMm)/(8a^(2))`
B. `(2GMm)/(3a^(2))`
C. `(7GMm)/(sqrt(2)a^(2))`
D. `(3GMm)/(a^(2))`

Answer

A

Explanation

`E=(Gmd)/((a^(2)+d^(2))^(3//2))=(sqrt(3)Gm)/(8a^(2))`
`F=ME=(sqrt(3)GMm)/(8a^(2))`