# Special relativity (mass-energy) Calculator

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

- 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.

[1] 2019/01/24 06:26 Female / 40 years old level / Others / Very /

- Purpose of use
- Determining yield of a liquid mercury-based RKV
- Comment/Request
- This is incredible.

[2] 2018/08/06 11:52 Male / Under 20 years old / High-school/ University/ Grad student / Very /

- Purpose of use
- Sci-fi writing.
- Comment/Request
- Holy, this calculator is amazing. Thanks.

[3] 2018/02/05 08:51 Male / 20 years old level / An office worker / A public employee / 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. ;-)

[4] 2018/01/31 17:34 Male / 60 years old level or over / A retired people / Very /

- Purpose of use
- Super useful for determining the power of a 2 cm diameter tungsten ball used in a Relative Kinetic Kill Vehicle.

[5] 2018/01/31 06:37 Male / Under 20 years old / High-school/ University/ Grad student / Very /

- Purpose of use
- Research into the destructive potential/ Hard Science fiction

[6] 2017/11/04 16:57 Male / 20 years old level / High-school/ University/ Grad student / Very /

- Purpose of use
- Generator

[7] 2017/07/25 10:18 Male / 60 years old level or over / Self-employed people / 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.

[8] 2016/09/27 13:04 Male / 50 years old level / An engineer / Very /

- Purpose of use
- Fact checking

[9] 2014/03/31 00:15 Male / 40 years old level / Others / Very /

- Purpose of use
- Double checking math, personal interest, non-school related.

[10] 2013/10/15 07:29 Male / Under 20 years old / High-school/ University/ Grad student / Very /

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