All Problems Elastic Waves. Acoustics.
Problem 4.178
A source of sound with natural frequency \(v_{0}=1.8 \mathrm{kHz}\) moves uniformly along a straight line separated from a stationary observer by a distance \(l=250 \mathrm{~m}\). The velocity of the source is equal to \(\eta=0.80\) fraction of the velocity of sound. Find: (a) the frequency of sound received by the observer at the moment when the source gets closest to him; (b) the distance between the source and the observer at the moment when the observer receives a frequency \(v=v_{n}\)
(a) \(v=v_{0} /\left(1-\eta^{2}\right)=5 \mathrm{kH}\) (b) \(r=l \sqrt{1+\eta^{2}}=0.32 \mathrm{~km}\)