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Homework Help: Will sound be affected by gravity in this simple problem?

  1. Feb 20, 2012 #1
    1. The problem statement, all variables and given/known data
    Assume the air temperature is 10.8o C, and the speed of sound in air is 337.8 m/s. Suppose the lab floor is 2.61 m beneath the motion detector. If the detector produces a click, how long would it take before the echo returned?

    2. Relevant equations
    s=Vi*t + (.5)*(a)*(t^2)

    3. The attempt at a solution
    I just wanted to make sure I'm doing this correctly.

    When going down:
    distance = Vi(t) + (.5)*a(t^2)
    2.61*2 (double distance) = 0 + [9.81*(t^2)] / 2
    10.44 / 9.81 = t^2
    t1 = 1.0316
  2. jcsd
  3. Feb 20, 2012 #2


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    Gold Member

    For one, you need to give us a better idea of the problem as a lot of this seems vague.

    Two, does that seem at all reasonable? Should sound take a whole second to travel only 2.6 meters?
  4. Feb 20, 2012 #3
    Found my mistake. I actually solved the answer correctly the first time (distance = v*t), but I accidentally input my answer incorrectly online. Woops :rolleyes:

    This thread can be deleted.
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