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Homework Help: Speaker Sound waves

  1. Nov 26, 2007 #1

    sun

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    1. The problem statement, all variables and given/known data
    A pair of speakers separatd by .700m are driven by the same oscillator at a frequency of 690Hz. An observer originally positioned at one of the speakers begins to walk along a line perpindicular to the line joining the speakers. How far mus the observer walk before reaching a relative maximum in intensity


    2. Relevant equations

    v(air)=345m/s

    r2-r1=n(lambda)

    3. The attempt at a solution

    How do i figure out the r values when only one side is given? I know i should use the pythagorean theorem here. I also know a relative maximum is constructive interference so i will use a full integer for n. r2-r2=1(lambda). I'm not sure what i'm missing here.

    i have:
    f=690Hz
    lambda=.5m
    T=.0015s

    suggestions would be appreciated.
    thanks
     
  2. jcsd
  3. Nov 26, 2007 #2

    rl.bhat

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    Homework Helper

    Let A an B are the positions of speakers and C is the position of the observer. When observer listenes maximum intensity, the path difference CB -CA = lamda = 0.5 m. According to pythagorean theorem CB^2 - CA^2 = AB^2. Solve these equations and find the distance CA of the observer.
     
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