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Course: AP®︎/College Physics 1 > Unit 9

Lesson 7: Doppler effect
Science
AP®︎/College Physics 1
Waves and sound
Doppler effect
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Doppler effect: Wavefront diagrams and word problems

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Problem

A speaker at rest plays a sound with constant frequency f0 near a straight train track. Train A moves toward the speaker, and train B moves away from the speaker.
How does the frequency, fA, observed by a rider on train A compare to the frequency, fB, observed by a rider on train B?
Choose 1 answer: