Actually it's
and it says that the energy of an object (E) is equal to the mass (m) of the object multiplied with the squared speed of light (
). This theory says that mass can be turned into energy and energy can be turned into mass. This is one of Einstein's theory of relativity.
True, an object at rest stays and rest and an object in motion stays in motion
The non-relativistic formula for low speed v < 0.1c is:
K.E = 0.5mv^2 = 0.5 * 235 * (7)^2 = 5757.5 J
The basic relationship between wavelength
, frequency f and speed c of an electromagnetic wave is
where c is the speed of light. Substituting numbers, we find: