Pneumatic motor success with pneumatic motors in the locomotive industry. In 1911 he designed a pneumatic locomotive and sold the patent to the H.K. Porter Company in Pittsburgh for use in coal mines. Because pneumatic motors do not use combustion they were a much safer option in the coal industry. Many companies claim to be developing Compressed air cars, but none are actually available for purchase or even independent testing. Impact wrenches, pulse tools, nutrunners, screwdrivers, drills, grinders, die grinders, sanders, dental drills and other pneumatic tools use a variety of air motors. These include vane type motors, turbines and piston motors.
Potential energy change in the potential energy associated with the force. The negative sign provides the convention that work done against a force field increases potential energy, while work done by the force field decreases potential energy. Common notations for potential energy are "PE", "U", "V", and "E". Potential energy is the energy by virtue of an object's position relative to other objects. Potential energy is often associated with restoring forces such as a spring or the force of gravity. The action of stretching a spring or lifting a mass is performed by an external force that works against the force field