Work Done Against Gravity - Practice Questions & MCQ

The gravitational potential energy at height 'h' from the earth's surface

Is given by

So at the surface of earth put h=0

We get

So if the body of mass m is moved from the surface of earth to a point at height h from the earth's surface

Then there is a change in its potential energy.

And this change in its potential energy is known as work done against gravity to move the body from earth surface to height h.

Where work done

change in Potential energy

distances

Putting r₁=R , and r₂=R+h

So

1. when 'h' is not negligible

2. when 'h' is very small

         As

           But is small as compared to earth's radius

           So

3. If h = nR then