Relativistic kinetic energy of rigid bodies


In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
In classical mechanics, the kinetic energy of a non-rotating object of mass m traveling at a speed v is equal to the mass multiplied by the square of the speed, multiplied by the constant 1/2.
In relativistic mechanics, this is a good approximation only when v is much less than the speed of light.
The work expended accelerating an object from rest to a relativistic speed is related to the velocity, the mass and the speed of light.
(The equation shows that the energy of an object approaches infinity as the velocity v approaches the speed of light c, thus it is impossible to accelerate an object across this boundary).

Related formulas


EkRelativistic kinetic energy (J)
mMass (kg)
cSpeed of light
vVelocity (m/sec)