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Homework Help: Rock is dropped off of a cliff physics homework

  1. Dec 14, 2004 #1
    I just started physics about a week ago. We got this problem for extra credit, and I need help with it.

    A rock is dropped off of a cliff and the sound of splashing water is heard 3.4 seconds later. The speed of sound is 340 m/s. How high is the cliff?

    Any insight/help you could give me would be great.

  2. jcsd
  3. Dec 14, 2004 #2


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    The height of the cliff is

    [tex]h = \frac {1}{2} g t_1^2[/tex]

    But h is also given by

    [tex]h = c_s (3.4 s - t_1)[/tex]

    where [itex]c_s[/itex] is the speed of sound. Can you take it from there?
  4. Dec 14, 2004 #3
    Yeah, thanks a lot
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