A.M.D.G.
Doppler Effect
Name: ____________________________
Date _________
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1. A train is blowing its whistle at a frequency of 550 Hz while moving away from you at
32 m/s. You are standing still on a platform watching it leave.
a. What frequency do you hear?
b. You notice a guy pass you on the tracks chasing the same train with his bicycle.
He’s moving towards the train at 14 m/s, trying to catch up it. What frequency
does he hear?
A.M.D.G.
Doppler Effect
c. Suddenly the train stops and reverses direction, still blowing its horn, but now
moving 18 m/s backwards towards you. What frequency
do you hear as it approaches you?
d. The bicyclist is looking down and doesn’t notice the train reversed and is
approaching him at 18 m/s, so he keeps pedaling at 14 m/s towards the train.
However, he notices that the frequency he previously heard in part (b) has now
changed. That makes him suspicious that something has changed. What
frequency does the bicyclist hear?