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Homework Help: Test tomorrow please help

  1. Dec 2, 2007 #1
    Test tomorrow...please help!!!!

    1. The problem statement, all variables and given/known data
    A student in a parked car honks the horn, which has a `proper' frequency of 310.00 Hz. An observer in an approaching vehicle measures the frequency of the sound to be 342 Hz. Calculate the speed of the approaching vehicle. Use 340 m/s as the speed of sound in air.

    2. Relevant equations

    3. The attempt at a solution
    Fs = 310 Hz
    Fo = 342 Hz
    Vo = 0 m/s
    V = 340 m/s
    Vs = ?

    I know
    Vs = (Fs - Fo / Fs + Fo) * V
    if the object is going away from the observer
    but how I do calculate if the object is approaching the person?
  2. jcsd
  3. Dec 2, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You already have a thread open on this same question. Use it.
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