A railway engine moving with a speed of 60 m/s passes in front of a stationary listener. The real frequency of the whistle is 400 Hz. Calculate the apparent frequency heard by the listener
(a) When the engine is approaching the listener
(b) When the engine is moving away from listener (V=340 m/s)

Explanation

`f_(1)=f[(V)/(V-V_(S))]=400[(340)/(340-60)]=485.7HZ`
(b) `f_(2)=f[(V)/(V+V_(s))]=400[(340)/(340+60)]=340Hz`