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Homework Help: Hydrostatics question

  1. Jan 26, 2007 #1


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    1. The problem statement, all variables and given/known data
    An empirical formula relating pressure and density for seawater w/ temperature constant is:
    p/pa = (k+1)(d/da)^7-k
    pa - pressure condition on the surface
    da - density condition on the surface
    k - dimensionless constant
    Using this formula in the hydrostatics relation, determine the pressure as a function of depth.

    2. Relevant equations
    Hydrostatic relation: dp/dz = -dg where d is density

    3. The attempt at a solution
    I tried to replace d w/ P/RT and then T w/ T0-kz to get the equation in terms of z. When I tried to take the derivative it was getting very complicated and I couldn't get it to work. I think I'm just approaching the problem incorrectly. I was wondering exactly how to start this problem. I know in order to take the derivative w/ respect to z there needs to be a z in the equation.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jan 26, 2007 #2
    Why do you need to differentiate with the hydrostatic relation?
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