The diagram shows the various positions of a child in motion on a swing. Somewhere in front of the child a stationary whistle is blowing.
-At which position(s) will the child hear the lowest frequency for the sound from the whistle?
A)at both A and D
B)at B when moving toward A
C)at B when moving toward C
D)at C when moving toward B
E)at C when moving toward D

Question

The diagram shows the various positions of a child in motion on a swing. Somewhere in front of the child a stationary whistle is blowing. 
-At which position(s) will the child hear the lowest frequency for the sound from the whistle?
A)at both A and D 
B)at B when moving toward A 
C)at B when moving toward C 
D)at C when moving toward B 
E)at C when moving toward D

Quizplus · Accepted Answer

As the child moves towards the whistle (from position C to position B), the distance between the child and the whistle reduces, causing an increase in frequency. Similarly, as the child moves away from the whistle (from position B to position C), the distance between the child and the whistle increases, causing a decrease in frequency.

Therefore, the child will hear the lowest frequency when moving from position C to position B, meaning the correct choice is D.

The Diagram Shows the Various Positions of a Child in Motion