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Physics Waves And Oscillations Level: High School

Doppler Effect

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 as a G which has a frequency of 392 Hz . What is the speed of the train ? The speed of sound in air is 343 m/s .

a) 26 m/s

b) 12 m/s

c) 42 m/s

d) 7.3 m/s

e) 37 m/s