Engine (such as pneumatic motors), springs (clockwork motors) and elastic bands. Historic military siege engines included large catapults, trebuchets, and (to some extent) battering rams were powered by potential energy. A pneumatic motor is a machine that converts potential energy in the form of compressed air into mechanical work. Pneumatic motors generally convert the compressed air to mechanical work though either linear or rotary motion. Linear motion can come from either a diaphragm or piston actuator, while rotary motion is supplied by either a vane type air motor or piston air motor. Pneumatic motors have found widespread success in the hand-held
Potential energy the negative of this scalar field so that work by the force field decreases potential energy, that is In this case, the application of the del operator to the work function yields, and the force F is said to be "derivable from a potential." This also necessarily implies that F must be a conservative vector field. The potential "U" defines a force F at every point x in space, so the set of forces is called a force field. Given a force field F(x), evaluation of the work integral using the gradient theorem can be used to find the scalar