Engine Engine An engine or motor is a machine designed to convert one form of energy into mechanical energy. Heat engines burn a fuel to create heat which is then used to do work. Internal combustion engines are heat engines that burn fuel in a combustion chamber to extract work from the pressure of expanding gases. Electric motors convert electrical energy into mechanical motion; pneumatic motors use compressed air; and clockwork motors in wind-up toys use elastic energy. In biological systems, molecular motors, like myosins in muscles, use chemical energy to create forces and eventually motion. The word "engine" derives from
Potential energy of solar matter per second into electromagnetic energy, which is radiated into space. Potential energy is closely linked with forces. If the work done by a force on a body that moves from "A" to "B" does not depend on the path between these points, then the work of this force measured from "A" assigns a scalar value to every other point in space and defines a scalar potential field. In this case, the force can be defined as the negative of the vector gradient of the potential field. For example, gravity is a conservative force. The associated potential is