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 "q" and "ε" is the vacuum permittivity. This may also be written using Coulomb's constant . If the electric charge of an object can be assumed to be at rest, then it has potential energy due to its position relative to other charged objects. The electrostatic potential energy is the energy of an electrically charged particle (at rest) in an electric field. It is defined as the work that must be done to move it from an infinite distance away to its present location, adjusted for non-electrical forces on the object. This energy will generally be non-zero if there is