Question

A train moving at a constant speed is passing a stationary observer on a platform. On one of the train cars, a flute player is continually playing the note known as concert A (f = 440 Hz). After the flute has passed, the observer hears the sound with a frequency of 415 Hz. What is the speed of the train? The speed of sound in air is 343 m/s.

Answer 1

Step-by-step explanation:

We shall apply the formula of Doppler effect here

F( APPARENT) = F( REAL ) X V/(V + Vs) [ v is velocity of sound and Vs is velocity of source.

415 = 440 X 343/343+Vs

142345 + 415Vs = 150920

415 V₀ = 8575

V₀ = 20.66 m/s.