When does the gravitational potential energy of a body become zero?

At what height above the surface of the earth is the gravitational potential energy of a body equal to that on the surface of the moon ? Assume that the mass of the earth is 80 times that of the moon and the radius of the earth is 4 times that of the moon. Given ,Radius of the earth =6400 km.

The change in the gravitational potential energy when a body of mass m is raised to a height nR above the surface of the earth is (here R is the radius of the earth)

Derive an expression for gravitational potential energy of a body at a distance r from earth.

The gravitational potential energy of a body on the surface of the earth is -6.4xx10^6 joule. Explain the statement.

If a body of mass m is at a distance r in the gravitational field of a body of mass M , what will be the gravititional potential energy of the body ?

Work done becomes zero

What is elastic potential energy ?