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.
Mechanical resonance the only frequency at which it will vibrate, is given approximately, for small displacements, by the equation: where "g" is the acceleration due to gravity (about 9.8 m/s near the surface of Earth), and "L" is the length from the pivot point to the center of mass.(An elliptic integral yields a description for any displacement). Note that, in this approximation, the frequency does not depend on mass. Mechanical resonators work by transferring energy repeatedly from kinetic to potential form and back again. In the pendulum, for example, all the energy is stored as gravitational energy (a form of potential energy)