Special Relativity Applied to Arbitrary Motion

The extension of special relativity (SR) to arbitrary motion, including accelerated, and general relativity (GR) constitutes the basics of this joint study of SR and GR, in terms of the same spacetime formulation, presenting a consistent theory. The GR principle of equivalence, however, is shown to have problems, when not formulated as originally stated by Einstein - a freely-falling observer in a gravitational field does not feel gravity. There is no statement that acceleration produces gravity. All accelerated particles can be transformed and seen as in uniform motion. Time cannot be uniquely split from spacetime, and the same is true with space. In general, time seems to tick slower for a comoving (i.e., same position and velocity) clock than for a non-comoving one (this is due to the finite speed of propagation). This work serves as a basis for GR, although GR is not regularly offered at undergraduate level. The laws of SR are just simpler when they work in-between inertial frames, as originally stated.