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Homework Help: Harmonic Sound Wave (pls advise)

  1. May 10, 2004 #1
    Hi all,

    can somebody advise on this,

    Equation:
    P (change in pressure) = p (density of gas)*w*v*s(max displacement amplitute)

    P = pwvs

    Needed to know, is the density of gas always at 1.29kg/m(3)?

    I've this following qeustion:
    A piston at one end of a long tube filled with air at room temperature and normal pressure oscillates with a frquency at 500Hz and an amplitude of 0.1mm. What is the intensity of the waves?

    answer:
    P=pwvs
    = 1.29*2pie(500)*340*1E-4
    = 138Pa

    if the density of gas does not always = 1.29kg/m(3), then how can I calculate the density of gas from the above question?

    thanks
    cseet
     
  2. jcsd
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