A uniform ring of mass M and radius R is placed directly above a uniform sphere of mass 8 M and of same radius R. The centre of the ring is at a distance of d=√3Rfrom the centre of the sphere. The gravitational attraction between the sphere and the ring is
√3GM2R2
Gravitational field due to the ring at a distance d=√3R on its axis is:
E=GMd(R2+d2)2/3=√3GM8R2Force on sphere=8ME=√3GM2R2