Describe the Doppler effect.
A student swings a whistle in a horizontal circle of radius 0.75 m0.75 \text{ m}0.75 m at a constant speed. The whistle emits sound in all directions at a single frequency of f0=1500 Hzf_0 = 1500 \text{ Hz}f0=1500 Hz.
An observer stands a large distance away and holds a microphone in the plane of the circle.
The whistle completes exactly 2.02.02.0 revolutions per second.
Show that the speed of the whistle in its circular path is approximately 9.4 m s−19.4 \text{ m s}^{-1}9.4 m s−1.
The speed of sound in air is 340 m s−1340 \text{ m s}^{-1}340 m s−1. Calculate the maximum frequency of the sound detected by the observer.
Calculate the minimum frequency of the sound detected by the observer.
