Solution:

Let the radius of the ring be r

Let the mass of the ring be m

When small element dM is considered as the mass, the gravitation force becomes,

where

The distance between m and the ring becomes 2h when the force is integrated.

Solution:

Let the radius of the ring be r

Let the mass of the ring be m

When small element dM is considered as the mass, the gravitation force becomes,

where

The distance between m and the ring becomes 2h when the force is integrated.