ABSTRACT
In this chapter, the authors discuss two main topics. The first of these is a more extended discussion of momentum and energy, with particular emphasis on the transformation of these quantities between two inertial frames. The second topic is the concept of force in relativistic dynamics—the way in which it is defined, its transformations, and the limitations on its usefulness. The authors begin with an important invariant that can be constructed from the measured values of momentum and energy in a given frame. The Lorentz transformations can be regarded as a prescription for transforming the various components of a 4-vector from one set of axes to another—often described as the “mapping” of the vector onto various coordinate systems in the four-dimensional world. This way of representing the relativistic scheme of things is attractive in a formal sense, and can also be very useful if one has once learned to exploit it—which primarily means developing the appropriate fluency in matrix algebra.
