# Talk:Einstein's Mass-Velocity Equation

Technically speaking, this is misleading. The mass of an object doesn't change at high speeds - the only mass that makes any sense to refer to is the rest mass, in fact, the difference is that $\mathbf{p}=m\dfrac{1}{\sqrt{1-\dfrac{v^2}{c^2}}}\mathbf{v}$. That is, momentum in relativity is not the same as momentum in Newtonian mechanics - it gains a $\gamma=\dfrac{1}{\sqrt{1-\dfrac{v^2}{c^2}}}$ term. See wikipedia on mass in special relativity for a fuller discussion. I don't know what other people's thoughts are, but I'd say this needs some rewording (or maybe should be scrapped entirely in favor of a relativistic definition of momentum). --Alec (talk) 05:12, 19 November 2010 (UTC)