Gravitational Potential energy

A body has energy if it is capable of doing work. In this case it is the position of the body in a gravitational field that gives it this possibility.


The energy associated with the position of a body of mass m in a gravitational field is the gravitational potential energy of the body compared with some chosen reference point where h = 0, usually the surface of the Earth. (Figure 1)


where g is the intensity of the gravitational field (assumed uniform here) and h is the vertical distance moved in the field.

The energy is converted to other forms when the gravitational potential energy changes due to a movement within the field. (Figure 2) If the distance moved parallel to the gravitational field is Dh then the change in potential energy is:

It is important to realise that D h is measured parallel to the field. Any other direction of movement will cause a smaller change in the gravitational potential energy and a body that moves at right angles to the field will have no change at all in their gravitational potential energy.