In the formula E=MC2 the "C" stands for velocity of light in meters per second. (300,000,000) and "M" is for mass in the metric system. This is difficult to apply in the English system but E=1/2KMV2.....here the "M" is for mass but the unit of mass in the English system is a slug.....or 32 pounds.
E=mc^2 is not really applicable here, as it describes the total relativistic energy, and we're talking about classical kinetic energy.
