We call these forms ordered energy . Gravitational potential energy is an example of ordered energy. The gravitational potential energy stored in a car on top of a hill is converted into kinetic energy as it rolls towards the bottom of the hill. Hydroelectric plants convert the gravitational potential energy stored in the water in a reservoir into electric energy. Kinetic energy also can be easily converted.
Kinetic energy is the energy an object has because it is moving.
There is however a form of energy, thermal energy , which cannot easily and completely converted into other forms. Thermal energy is disordered energy. The individual atoms and molecules that make up an object have potential and kinetic energy, but they move in a random fashion about their equilibrium position in the object, so that the object as a whole remains at rest. The more kinetic energy is stored in the random motion of the atoms or molecules, the higher is the temperature of the object. Macroscopically, forces that do work converting ordered energy into disordered energy are non-conservative forces .