Answer:
a) Your player
b) Observer's player
c) Each measures their own first
Explanation:
Because given problem is having relative velocity to each other. The person sitting on the train is moving with a very high speed relative to the person standing next to the track.
In this case, the clock situated in the train will be running slow with respect to the stationary frame of reference
The product of (frequency) times (wavelength) is always
the same number (the speed of the wave).
So if the frequency is doubled, the wavelength has to drop to
half of what it was, in order to keep their product constant.
