[deleted]
Azzam/Roger
Except that, it is best to follow what Einstein defined SR as:
Einstein SR & GR 1916 section 18:
"...the special principle of relativity, i.e. the principle of the physical relativity of all uniform motion... Up to the present, however... provided that they are in a state of uniform rectilinear and non-rotary motion...The validity of the principle of relativity was assumed only for these reference-bodies, but not for others (e.g. those possessing motion of a different kind). In this sense we speak of the special principle of relativity, or special theory of relativity. In contrast to this we wish to understand by the "general principle of relativity" the following statement: All bodies of reference are equivalent for the description of natural phenomena (formulation of the general laws of nature), whatever may be their state of motion".
Einstein Foundation of GR 1916 section 3:
"...But we wish to show that we are to abandon it and in general to replace it by more general conceptions in order to be able to work out thoroughly the postulate of general relativity, the case of special relativity appearing as a limiting case when there is no gravitation"
Einstein SR & GR 1916 section 28:
"The special theory of relativity has reference to Galileian domains, ie to those in which no gravitational field exists. In this connection a Galileian reference body serves as body of reference, ie a rigid body the state of motion of which is so chosen that the Galileian law of the uniform rectilinear motion of isolated material points holds relatively to it... In gravitational fields there are no such things as rigid bodies with Euclidean properties; thus the fictitious rigid body of reference is of no avail in the general theory of relativity"
Paul