Re: What is gravitational potential energy?

Potential energy is a kind of 'stored' energy that can be used
to do work. Examples would be the energy stored in a spring
when you compress it, or in a bow when you stretch the string.

Gravitational potential energy is energy stored when an object
is moved away from another object which attracts it through the
force of gravity. For example, when water is lifted up, say by 
a dam or water wheel, it can do work as it falls back down.
The farther away the two objects are moved, the more potential
energy is stored.

Understanding gravitational potential energy is important in
many areas of science, from ballistics to the formation of stars.

Pauline Barmby
pbarmby@cfa.harvard.edu