Does enistein 1st postulate and 2nd postulate only apply to light or do they apply to real life situation. For instance, if I travel in my car will I experience time differently then if I sit at home?
Realtivity applies to real life situations as well as light. But because the car speed is so slow compared to the speed of light that the effects on you and any observers are neglegible. If your car travelled at 50MPH, that's about 13.5 million times slower than the speed of light. So that any effects on you are not noticeable.
