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Sound Problem

  1. May 10, 2003 #1
    Sound Problem....

    A swimmer with one ear underwater and one ear above water in air, hears a crash. She hears the crash in the water first where the Veloctiy of the wave in water was 1500m/s. The air temperature is 20°C and she hears the wave again after 2.0 seconds but this time she hears it through the ear thats above the water. Find the distance from the crash....

    What I tried was this:

    -Vair=332 + 0.59 (20°) = 343.8m/s

    -Since she hears the sound in air 2 seconds after it must've travelled at least 343.8*2 = 687.6 m

    So is the distance is 687.6 m?

    Thx for help....
  2. jcsd
  3. May 10, 2003 #2
    Try again.

    Let t = time it took for the sound to arrive in water.

    Now, in terms of t, how long did it take in air?

    See if you can do anything with that...
  4. May 10, 2003 #3
    Im sorry I dont understand...If i find the ratio of the time it took for water than air, how will that help me?
  5. May 10, 2003 #4


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    Ok, you know the speed of sound in air at 20 degrees, right?

    let x be the distance...
    x/1500 = t1 (time taken in water)

    x/speed of sound in air (20C) = t2

    t2 = t1 + 2 (since it is two seconds later)

    x/speed of sound in air(20 C) = x/1500 + 2

    Now, solve.
  6. May 11, 2003 #5
    k thx ill try that
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