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Homework Help: What is the density of air? Need it in 2 hours

  1. Apr 26, 2010 #1
    what is the density of air? Need it in 2 hours!!!

    1. The problem statement, all variables and given/known data

    For a gas at pressure P, the Bulk modulus B (under adiabatic conditions of change) is g · P. At a certain temperature, at normal atmospheric pressure, the velocity of sound in air is found to be 339.5 m/s. If g for air is 1.40, what is the density of air (in kg/m3) at that temperature ?

    2. The attempt at a solution

    Given wavelength, and v, then I found f:

    f = v / wavelength = 242.5 Hz.

    I know that:

    B = v^2 * p

    and B = wavelength * P

    => v^2 * p = wavelength * P

    but how to find P?

    I need it in couple of hours. Please advise!

    Thanks a lot!
  2. jcsd
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