What is a variable speed drive? A variable speed drive is a piece of equipment that regulates the speed and rotational force, or torque output, of an electric motor. The background and technology. There are millions of motors in use in industry and offices around the world.
The specific gravity for Obsidian is 2.35, it's refractive index is 1.48-1.51, and it's double refraction is None. History Obsidian is named after a Roman, Obsius.
As specific gravity is just a comparison, it can be applied across any units. The density of pure water is also 62.4 lbs/ftÂ³ (pounds per cubic foot) and if we know that a sample of aluminum has a sg of 2.5 then we can calculate that its density is 2.5 x 62.4 = 156 lbs/ftÂ³.