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Homework Help: Sound homework help please

  1. Nov 8, 2005 #1
    Ok I need guidance on how to approach this problem. The problem is as follows: A stone is dropped from the top of a cliff. The splash it makes when striking the water below is heard 3.5s later. How high is the cliff?
  2. jcsd
  3. Nov 8, 2005 #2
    Does anyone know the answer to this problem?
  4. Nov 8, 2005 #3
    the time is of course the time for it to fall plus the time for the sound to come back up. So therefore use [tex]d=\frac{1}{2}at^2[/tex] and [tex]v_{sound}=\frac{d}{t}[/tex] then you solve both for time and add them together to produce 3.5 and hence solve for d.
  5. Nov 8, 2005 #4
    ok I had those equations I just didn't think what to do. CAn you help me with this problem also: At a rock concert, a dB meter registered 130 dB when placed 2.8m in front of a loudspeaker on the stage. What is the power output of the speaker, assuming uniform spherical spreading of the sound and neglecting absorption in air?

    Someone help me plz?
    Last edited: Nov 8, 2005
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