Doppler effect: A plane flies toward a stationary siren at 1/4 the speed of sound. Then the plane stands still on the ground and the siren is driven toward it at 1/4 the speed of sound. In both cases, a person sitting in the plane will hear the same frequency of sound from the siren.

Question

Quizplus · Accepted Answer

The Doppler effect depends on the relative motion between the source and the observer. When the plane moves towards the stationary siren, the frequency increases due to the plane's motion. When the siren moves towards the stationary plane, the frequency increases due to the siren's motion. However, the changes in frequency are not identical because the Doppler effect formula differs for moving sources and observers.

Doppler Effect: a Plane Flies Toward a Stationary Siren at 1/4