Delta-v (physics) such as determining the change in momentum (impulse), where :formula_4, where formula_5 is momentum and m is mass. Delta-v (physics) Delta comes as the 4th letter in the greek alphabets which is spell as 'D' in the english alphabets . In general physics, delta-"v" is simply a change in velocity. The Greek uppercase letter delta is the standard mathematical symbol to represent change in some quantity. Depending on the situation, delta-"v" can be either a spatial vector (Δv) or scalar (Δ"v"). In either case it is equal to the acceleration (vector or scalar) integrated over time: If acceleration is constant,
Mass–energy equivalence the velocity is small, the relativistic mass and the rest mass are almost exactly the same. Also Einstein (following Hendrik Lorentz and Max Abraham) used velocity- and direction-dependent mass concepts () in his 1905 electrodynamics paper and in another paper in 1906. However, in his first paper on (1905), he treated as what would now be called the "rest mass". Some claim that (in later years) he did not like the idea of "relativistic mass". When modern physicists say "mass", they are usually talking about rest mass, since if they meant "relativistic mass", they would just say "energy". Considerable debate