Potential Energy

Potential Energy, stored energy possessed by a system as a result of the relative positions of the components of that system. For example, if a ball is held above the ground, the system comprising the ball and the earth has a certain amount of potential energy; lifting the ball higher increases the amount of potential energy the system possesses. Other examples of systems having potential energy include a stretched rubber band, and a pair of magnets held together so that the like poles are touching.

Work is needed to give a system potential energy. It takes effort to lift a ball off the ground, stretch a rubber band, or force two magnets together. In fact, the amount of potential energy a system possesses is equal to the work done on the system. Potential energy also can be transformed into other forms of energy. For example, when a ball is held above the ground and released, the potential energy is transformed into kinetic energy.

Potential energy manifests itself in different ways. For example, electrically charged objects have potential energy as a result of their position in an electric field. An explosive substance has chemical potential energy that is transformed into heat, light, and kinetic energy when detonated. Nuclei in atoms have potential energy that is transformed into more useful forms of energy in nuclear power plants (see Nuclear Energy).