1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Power and Amplitude of sound wave

  1. Nov 6, 2005 #1
    For my homework,
    To find Amplitude of the wave,
    for a longitudinal wave travelling down a copper rod.
    Given: frequency, radius of copper rod, average power, Young's constant, density, wavelength.
    what equation should I consider?
    I'm thinking something like P=(omega*amplitud)^2 because I know power is proportional to amplitude and frequency of the wave....but I know that's wrong.
     
  2. jcsd
  3. Nov 7, 2005 #2

    Astronuc

    User Avatar

    Staff: Mentor

    The displacement amplitude A is given by:

    [tex]A\,=\,\frac{\Delta{p_o}}{\omega\,\rho\,c}[/tex], where

    [itex]\Delta{p_o}[/itex] is the pressure amplitude,

    [itex]\omega[/itex] is the angular frequency given by [itex] 2\,\pi\,f[/itex],

    [itex]\rho[/itex] is the material density, and

    c = speed of sound in the material, which is given by -

    [tex] c = \sqrt{\frac{E}{\rho}}[/tex]

    where E is Young's (Elastic) modulus.


    The intensity of the sound wave is I = P/a, where P is the power of the wave per unit transverse area, a, and

    P = 1/2 [itex]\omega^2[/itex]A2[itex]\rho[/itex] c
     
    Last edited: Nov 7, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Similar Discussions: Power and Amplitude of sound wave
Loading...