To calculate kinetic energy (in Joules) we used this formula: KE ( in Joules) = 0.5 ( a half) x the mass of the something (in kg) x the speed squared (in Meters/Second). or. KE = 0.5 . m . v^2. As an example for the above formula; a .20 gram bb is moving at 328 feet per second [. read more