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