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mfb
#3
Dec5-12, 08:12 AM
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P: 11,904
As far as we know, physics is the same in all reference frames - there is no "absolute velocity". If you don't look out of the window, you cannot measure the speed relative to the ground (neglecting issues with wheels, sound from the motor and so on).
This is a fundemental concept in the theory of special relativity.

There are several other motions which would be relevant otherwise:
- earth rotates around its center, the surface moves with ~300m/s (depending on your latitude) relative to its center
- earth rotates around sun with ~30km/s
- the solar system rotates around the galactic center with ~200km/s
The train is slow compared to that.