Generalised Einstein mass-variation formulae: I Subluminal relative frame velocities

Much of the formalism in special relativity is intimately bound up with Einstein’s formula for the variation of mass m with its velocity v  , namely m(v)=m0∗[1-(v/c)2]-1/2, where m is the mass, v the velocity, c   denotes the speed of light and m0∗ denotes the rest mass, noting that in these papers, we employ an asterisk to designate the rest mass. Einstein’s formula together with the Lorentz transformations and their consequences are fundamental to the development of special relativity. Here we introduce the notion of the residual mass m0(v)m0(v) which for v