What are the units for the equation E=gamma*m?

[lavenderblue]

I'm using the equation: E=gamma*m

I want to know what the units of each of the quantities are. If I want to calculate the Lorentz factor, then do I need to make sure that both the Energy and mass have the same units?

I am also using the equation for length contraction: L=L0*gamma

Do I need to make sure that the length is in metres? And is L0 the length in the rest frame?

 

[Delphi51]

The formula relating E and m is E = mc². m in kg, E in Joules.
The gamma factor 1/sqrt(1-v²/c²) is dimensionless (no units).
It relates two times or lengths (moving to stationary measurements) as in length contraction and time dilation.

 

[Pengwuino]

You might want to take a look at this:

http://en.wikipedia.org/wiki/Natural_units

 

[Delphi51]

Oh, thank you! I haven't seen natural units for many years.
The article you linked answers your question: you must put the mass and energy in Planck units. The SI equivalents for the Planck units for mass and energy are listed in tables here:
http://en.wikipedia.org/wiki/Planck_units