# Special relativity (mass-energy) Calculator

## Calculates the mass-energy of a body moving with some relative velocity with respect to the observer.

 Rest mass m0 kg Relative velocity v km/s≦c 6digit10digit14digit18digit22digit26digit30digit34digit38digit42digit46digit50digit Rest mass energy E0 MJ Relativistic mass energy E MJ Mass energy rate E/E0 Velocity ratio to light v/c %
 $\normal Mass\ energy\\\vspace{5}\\\hspace{20}E_0=m_0 c^2\\\hspace{20}E={\large\frac{E_0}{\sqrt{1-{\large\frac{v^2}{c^2}}}}}={\large\frac{m_0c^2}{\sqrt{1-{\large\frac{v^2}{c^2}}}}}\\\hspace{20}c=299792.458km/s\\$

Special relativity (mass-energy)
 [1-10] /11 Disp-Num5103050100200
[1]  2019/01/24 06:26   Female / 40 years old level / Others / Very /
Purpose of use
To calculate the energy of an 866.67 fm³ mass of neutron degenerate matter at neutron star core density travelling at 99.9999% c.
[2]  2018/08/06 11:52   Male / Under 20 years old / High-school/ University/ Grad student / Very /
Purpose of use
Determining yield of a liquid mercury-based RKV
Comment/Request
This is incredible.
[3]  2018/02/05 08:51   Male / 20 years old level / An office worker / A public employee / Very /
Purpose of use
Sci-fi writing.
Comment/Request
Holy, this calculator is amazing. Thanks.
[4]  2018/01/31 17:34   Male / 60 years old level or over / A retired people / Very /
Purpose of use
Had a silly little idea I rattling around in my head for years. Thought I could prove it wrong and put it to bed. Turns out it''s valid to more than 16 decimal points. Now I have to kind a competent physicist and ask him how WTF??? Thanks so much, if I had found this site earlier I would be finished now. ;-)
[5]  2018/01/31 06:37   Male / Under 20 years old / High-school/ University/ Grad student / Very /
Purpose of use
Super useful for determining the power of a 2 cm diameter tungsten ball used in a Relative Kinetic Kill Vehicle.
[6]  2017/11/04 16:57   Male / 20 years old level / High-school/ University/ Grad student / Very /
Purpose of use
Research into the destructive potential/ Hard Science fiction
[7]  2017/07/25 10:18   Male / 60 years old level or over / Self-employed people / Very /
Purpose of use
Generator
[8]  2016/09/27 13:04   Male / 50 years old level / An engineer / Very /
Purpose of use
To determine what fraction of a mass would be needed to accelerate a mass to relativistic speeds. To accelerate to 0.2c about 2% of a mass would need to be converted to energy. I've been thinking about the Fermi Paradox and this was good information.
[9]  2014/03/31 00:15   Male / 40 years old level / Others / Very /
Purpose of use
Fact checking
[10]  2013/10/15 07:29   Male / Under 20 years old / High-school/ University/ Grad student / Very /
Purpose of use
Double checking math, personal interest, non-school related.

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