An observer approaches a stationary 1000 Hz sound source at twice the speed of sound. The observer hears a frequency of
A) 1500 Hz.
B) 500 Hz.
C) 4000 Hz.
D) 3000 Hz.
E) 2000 Hz.

Question

Quizplus · Accepted Answer

The observer is moving towards the sound source at twice the speed of sound, so the frequency of the sound waves reaching the observer will be increased by a factor of 3. Therefore, the observer will hear a frequency of 1000 Hz * 3 = 3000 Hz.

An Observer Approaches a Stationary 1000 Hz Sound Source at Twice