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An 80kg diver falls from a board into water 44m below the water.

  1. Oct 26, 2009 #1
    1. The problem statement, all variables and given/known data
    An 80kg diver falls from a board into water 44m below the water.

    A)I found the potential energy of the diver on the board is 34496
    B)kinetic energy as he stirkes the water=34496
    C)I can figure out "how long does it take the diver to strike the water"

    2. Relevant equations



    3. The attempt at a solution
    A)I found the potential energy of the diver on the board is 34496
    B)kinetic energy as he stirkes the water=34496
     
  2. jcsd
  3. Oct 26, 2009 #2

    Delphi51

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    Welcome to PF, qomoco.
    I think (a) and (b) are correct.
    For (c), use one of your accelerated motion formulas. You know the acceleration, right?
     
  4. Oct 26, 2009 #3
    the acceleration should be gravity? so 9.8m/s^2 but I dont know what's the accelerated motion formula.

    umm. I took square root of (9.8x44x2) and got 29.36s but that's not right, the answer my teacher gave was 2.98s... can't figure out what I did wrong.
     
  5. Oct 26, 2009 #4

    Delphi51

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    The basic accelerated motion formulas are
    a = Δv/Δt, Vf = Vi + at, d = Vi*t + ½*a*t²
    You just have to pick out the one that makes use of your knowns and gives you the quantity you're looking for.
     
  6. Oct 26, 2009 #5
    dont forget [tex] {V_f}^2 = {V_o}^2 + 2ad [/tex] :)
     
  7. Oct 26, 2009 #6

    DaveC426913

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    It makes no sense that this guy is a diver. There are only two possibilities that make sense...
    1] This is a two-part question. The second part deals with what happens after he hits the water.
    2] You have misunderstood the question and/or mistranscribed it. Perhaps the ...



    [ EDIT ] Oh. A swimmer diver.

    I was picturing a guy in full scuba gear falling into the water from 120ft. It would kill him. Shows you where my head is at...
    :blushing: :rolleyes: :blushing: :rolleyes:
     
  8. Oct 26, 2009 #7

    Delphi51

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    Oh - 44 m is a pretty high diving board!
    I guess the physics department computer needed a lot of random questions so it ran the range up a bit!
     
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