A train is whistling while approaching a tunnel at a speed of 36 kmph. The driver hears the echo of the whistle reflected from the tunnel and estimates its frequency to be 850 Hz. Find the actual frequency of the whistle. The velocity of sound in air = 330 m//s

A train is whistling while approaching a tunnel at a speed of 36 kmph.

1.	A train is whistling while approaching a tunnel at a speed of 36 kmph. The driver hears the echo of the whistle reflected from the tunnel and estimates its frequency to be 850 Hz. Find the actual frequency of the whistle. The velocity of sound in air = 330 m//s
Answer» ANSWER :800 HZ