Question:
A person riding a car moving at $72 \mathrm{~km} \mathrm{~h}^{-1}$ sound a whistle emitting a wave of frequency $1250 \mathrm{~Hz}$. What frequency will be heard by another person standing on the road
(a) in front of the car
(b) behind the car? Speed of sound in air $=340 \mathrm{~m} \mathrm{} \mathrm{s}^{-1}$.
Solution:
