(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two trains emit whistles of the same frequency, 282 Hz. If one train is at rest and the other is traveling at 45 km/h away from an observer at rest, what beat frequency will the observer detect?

2. Relevant equations

3. The attempt at a solution

I used listener behind formula and got an answer of 544 Hz because i doubled the Frequency source. The answer is wrong, please help me!Thanks!

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# Homework Help: What beat frequency will the observer detect?

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