Conservation of Momentum and Angular Momentum in Relativistic Classical Particle Mechanics

Abstract

For a classical-mechanical system of two particles, the conditions for Lorentz-invariant equations of motion are expressed in terms of relativistic momentum variables, and are shown to imply that neither the conventional total kinematic particle momentum nor the conventional total kinematic particle angular momentum is a constant of the motion unless the accelerations are zero. This is compared with a theorem of Van Dam and Wigner.