A boy riding on a bicycle going at 12 km h-1 towards a vertical wall whistles at his dog on the ground. If the frequency of the whistle is 1600 Hz and the speed of sound in air is 330 m s-1, find (a) the frequency of the whistle as received by the wall (b) the frequency of the reflected whistle as received by the boy.

(a)


The frequency of whistle received by the wall can be calculated by,



Here,


f0=1600 Hz


vs=12 kmph = 3.33 ms-1


v=330 m/s




(b)


Now 1616 Hz will act as source frequency.


So,


f0=1616 Hz


vs=12 kmph = 3.33 ms-1


v=330 m/s




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