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AP® Physics 1 & 2

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Whistle Frequency: Train Moving Away

APPH12-XLG95Y

Looking down the railroad tracks at a railroad crossing, you notice two identical trains with identical train whistles. One train is at rest and the frequency of this train's whistle is observed to be $f$. The second train is moving away from you (you are at rest) at a constant velocity.

As the train moves away, which of the following is true regarding the moving train's whistle frequency?

A

The train whistle frequency of the moving train is the same as that of the train at rest.

B

The train whistle frequency of the moving train is less than that of the train at rest.

C

The train whistle frequency of the moving train is greater than that of the train at rest.

D

There is not enough information to determine anything regarding the frequency of the moving train whistle.