An astute physics student is near a train track. As a train speeds by, the perceived frequency of the whistle changes from middle C to the A below middle C. If the initial perceived frequency of the whistle had been an octave above middle C, as the train whizzed by the frequency would have changed to A) the A above middle C. B) a frequency the A above middle C. C) a frequency

Question

An astute physics student is near a train track. As a train speeds by, the perceived frequency of the whistle changes from middle C to the A below middle C. If the initial perceived frequency of the whistle had been an octave above middle C, as the train whizzed by the frequency would have changed to
A) the A above middle C.
B) a frequency > the A above middle C.
C) a frequency < the A above middle C.
D) none of the above.

Quizplus · Accepted Answer

The perceived frequency of the whistle decreases as the train moves away from the observer. If the initial perceived frequency had been an octave above middle C, the final perceived frequency would be an octave below the A above middle C, which is the A below middle C.

An Astute Physics Student Is near a Train Track