Condition for the existence of relative motion

The motion of a body means its displacement relative to a reference system. However, the relative motion is a displacement of a reference system, which carries a moving body, relative to another reference system, which is at rest. The first motion can be called simple motion because it represents the motion of a single body with respect to a reference system; the second motion-relative motion-appears to be a compound motion because there are two simultaneous motions. While there is a difference between these two motions, physics can determine the condition of existence of relative motion. This is the aim of this study. The definition of this condition is very important for the correct explanation of relative motion. The theory of special relativity (TSR) consistently violates this condition in explaining relative motion. Due to this violation, the TSR often draws conclusions for relative motion involving simple motion. Thus, the violation of the conditions of the existence of relative motion results in erroneous conclusions in TSR. (C) 2014 Physics Essays Publication.