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!

How intensity and amplitude depends from a distance r

  1. Nov 8, 2009 #1
    1. The problem statement, all variables and given/known data
    A line source of sound (for instance, a noisy freight train on a straight track) emits a cylindrical expanding sound wave. Assuming that the air absorbs no energy, find how (a) the intensity I and (b) the amplitude sm of the wave depends on the perpendicular distance r from the source.

    2. Relevant equations
    Intensity = Power/Area

    3. The attempt at a solution
    I thought that the area would be something like the base of a circular cone, and the area of it base would A [tex]\propto[/tex] r². Then I [tex]\propto[/tex] r⁻². Is the reasoning right?
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted