Physics 9702 · AS & A Level · Doppler effect for sound waves
Doppler effect for sound waves — practice question
A sound source is tied to a rope and whirled round in a horizontal circle at constant speed, as shown in Fig. 5.1. The source has speed $12.0\,\text{m s}^{-1}$ and emits sound with frequency $951\,\text{Hz}$. The speed of sound in air is $330\,\text{m s}^{-1}$. An observer, positioned very far from the source, hears the sound.
(a)[2]
Calculate the minimum frequency of the sound heard by the observer, giving your answer to three significant figures.
(b)[2]
The source moves in a circle of radius $2.4\,\text{m}$. Determine the shortest time interval between the observer hearing the minimum-frequency sound and the observer hearing the maximum-frequency sound.
Worked solution & mark scheme
This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Apply $f_0=\frac{fv}{v+v_s}$” …