Answer to Question #167208 in Mechanics | Relativity for Satyam

Question

Write postulate of STR.

Answer 1

Postulates of STR:

STR deals with the inertial frames of reference and it is based on the following two postulates.

First Postulate: “All inertial frames are equivalent”. Therefore laws of physics must be invariant in all inertial frame frames. What this postulate implies is that, if an experiment is done in a laboratory and the same experiment is repeated in a van moving with constant velocity then result of experiment in the two cases will be same.

Second postulate: “Speed of light in vacuum has same value in all inertial frame and speed of light is the ultimate speed in vacuum”. What this postulate implies that,

• Speed of any object or anything cannot be greater than speed of light in vacuum.

• Magnitude of velocity of light is same in all inertial frames, but components of velocity of light changes. If velocity of photon w.r.t to S frame is v=c then velocity of photon w.r.t S’ frame is v’=c (i.e. same as in S frame).

• Velocity of any object (for example electron) can be greater than speed of light in