stylistic:style_transfer, stylistic:tone
Practical examples

Einstein used the centimetre–gram–second system of units (cgs), but the formula is independent of the system of units. In natural units, the numerical value of the speed of light is set to equal 1, and the formula expresses an equality of numerical values: E = m. In the SI system (expressing the ratio E / m in joules per kilogram using the value of c in metres per second):

So the energy equivalent of one kilogram of mass is

or the energy released by combustion of the following:

Any time energy is released, the process can be evaluated from an E = mc perspective. For instance, the " Gadget "-style bomb used in the Trinity test and the bombing of Nagasaki had an explosive yield equivalent to 21 kt of TNT. About 1 kg of the approximately 6.15 kg of plutonium in each of these bombs fissioned into lighter elements totaling almost exactly one gram less, after cooling. The electromagnetic radiation and kinetic energy (thermal and blast energy) released in this explosion carried the missing gram of mass.

Whenever energy is added to a system, the system gains mass, as shown when the equation is rearranged: