Abstract:
Physical (covariant and measurable) coordinates of free particles and covariant
coordinates of the center of mass of a system of particles are found for the three
basic forms of relativistic dynamics. For a system of two directly interacting
particles in the point form of dynamics, covariant coordinates are found and the
equations of motion reduced to a manifestly covariant form. These equations are
generalized to the case of interaction of the particles with an external electromagnetic
field.