What Is Potential Energy?

The energy possessed by an object by virtue of its position is called potential energy. One of the commonest forms of potential energy is that possessed by an object when it is above the level of the earth's surface. This is called gravitational potential energy and is described by the expression
          
                              PE = mgh

Where m is the mass of the object,g the acceleration due to the gravity and h the height of the object above the earth's surface.

There are many examples of potential energy. A stone held at some height above the ground has potential energy. Water in an elevated reservoir possesses potential energy. A stretched or compressed spring also has potential energy.

The concept of energy is much wider than the simple idea of kinetic and potential energies of a mechanical system. In addition to mechanical energy (kinetic & potential), there are several other forms of energy, e.g. heat energy, light energy, sound energy, nuclear energy etc.