A man is standing on a railway platform listening to the whistle of an engine that passes the man at constant speed without stopping. If the engine passes the man at time ${t_0}$. How does the frequency $f$ of the whistle as heard by the man changes with time
Diffcult
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(a) When the train is approaching the stationary observer frequency heard by the observer $n' = \frac{{v + {v_0}}}{v}n$
when the train is moving away from the observer then frequency heard by the observer $n'' = \frac{{v - {v_0}}}{v}n$
it is clear that $n'$ and $n''$ are constant and independent of time. Also and $n' > n".$
when the train is moving away from the observer then frequency heard by the observer $n'' = \frac{{v - {v_0}}}{v}n$
it is clear that $n'$ and $n''$ are constant and independent of time. Also and $n' > n".$
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