Problem
A person on a railroad car blows a trumpet note at 440 Hz.The car is moving towards a wall at 20.0 m/s assume sound speed is 343 m/s
calculate a) frequency of sound as received at the wall b) frequency of reflected sound arriving back at the original source
a) source moving vS= 20.0 m/s f=440Hz f ` = f (v/v-vS)=(440)(343)/(343-20)=467 Hz
b) source stationary f `= 467 Hz vD= 20.0 m/s f ``=f `(v+vD)/v=(467)(343+20)/343=494 Hz