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Homework Help: Finding the Net Force Exerted by Water (of certain depth) on A Dam

  1. Jan 21, 2009 #1
    1. The problem statement, all variables and given/known dataEvaluate the net force on a 200 -m high dam with a 60 mwater depth.

    2. Relevant equations
    p(hydrostatic pressure)=rhogh+patm

    3. The attempt at a solution
    The atmospheric pressure acts on both the dam and the water, so it cancels out of the equation. g=9.8m/s^2, rho=1,000 kg/m^3,d=60m

    F=P*A => dF= integral(rhogh)*(wdy) = rho*g*d*w (y) Integrated from y=0 to y=200
    =(1,000 kg/m^3 *9.8m/s^2*60m*200 w )-0

    But, I was not given width, so how else can I find the net force acting on the dam. All I know is that it remains constant.
    Last edited: Jan 21, 2009
  2. jcsd
  3. Jan 21, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Are you sure that 200 m is not the width of the dam? The only height that matters is the depth of the water.

    Not sure what you're doing here.
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