# Relativistic energy–momentum relation

## Description

In physics, mass–energy equivalence is the concept that the mass of an object or system is a measure of its energy content. A physical system has a property called energy and a corresponding property called mass; the two properties are equivalent in that they are always both present in the same proportion to one another. The equivalence of energy and mass is reliant on the speed of light, if the energy is the relativistic energy and the mass is the relativistic mass. It is also correct if the energy is the rest or invariant energy (also the minimum energy), and the mass is the rest mass, or the invariant mass. Connection of the total or relativistic energy with the rest or invariant mass requires consideration of the system total momentum, in systems and reference frames where the total momentum has a non-zero value. The formula of relativistic energy–momentum relation connect the two different kinds of mass and energy.

Related formulas## Variables

E_{r} | Total or Relativistic energy (J) |

m_{0} | Rest or Invariant mass (kg) |

c | Speed of light |

p | total momentum (kg*m/s) |