### relativistic energy

(energy of an object including relativistic effects)

The phrase **relativistic energy** generally means "energy, taking
relativity into account", or it means the contribution of
relativity to some type of energy, e.g., to kinetic energy. The formulas for
determining these are clear, but a terminology is not unanimously
used.

The term mass (i.e., with no qualifying adjective)
has come to be used two ways in light of relativity:
to mean the object's **rest mass**, which is the mass as we normally think of it,
or to mean a **relativistic mass**,
the mass equivalent of the object's total energy,
including kinetic energy and relativistic effects. (Effectively,
this potential terminology-confusion only arises due to relativity, and
the difference is only for a moving object, and significant
only if at relativistic speeds.)

Some formulas for energy that take relativity into account,
specifying which mass we mean here:

**rest energy** = M_{rest}C²
**total energy** aka **total relativistic energy** = γM_{rest}C²
kinetic energy = (γ-1)M_{rest}C²
relativistic contribution to kinetic energy = ((γ-1)C²-V²/2)M_{rest}
M_{rel} = γM_{rest}
rest energy = M_{rel}C²/γ
total energy = M_{rel}C²
kinetic energy = (1-1/γ)M_{rel}C²
relativistic contribution to kinetic energy = ((γ-1)C²-V²/2)M_{rel}/γ

- M
_{rest} - rest mass.
- M
_{rel} - total mass including the rest mass, and the mass-equivalent of kinetic energy including relativistic effects.
**γ** - Lorentz factor: (1-V²/C²)^{-½}
- C - speed of light.
- V - speed of the object.

(*physics,relativity,energy*)
http://en.wikipedia.org/wiki/Mass_in_special_relativity

http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/releng.html

**Referenced by:**

relativistic momentum

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