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Homework Help: What is the depth x of the oil?

  1. Jun 10, 2008 #1
    1. The problem statement, all variables and given/known data
    The bore hole of depth [tex]2000m[/tex] contains both oil and water as shown. The pressure at the bottom is [tex]17.5MPa[/tex]. The density of the oil is [tex]830kgm^-3[/tex] and the density of the water is [tex]1000kgm^-3[/tex].
    http://img384.imageshack.us/img384/6944/10062008fj0.png [Broken]
    What is the depth x of the oil?

    2. Relevant equations
    Pressure = Height x Density x Gravity

    3. The attempt at a solution

    [tex]17.5 \times 10^6 = x \times 1000 \times 9.81[/tex]

    [tex]x = \frac{17.5 \times 10^6}{1000 \times 9.81}[/tex]

    [tex]x = 1789.893986m[/tex]

    Where did I go wrong?
     
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Jun 10, 2008 #2
    Both oil and water have a contribution in the pressure:

    [tex] p = \rho g \Delta h [/tex]

    So we get:

    [tex]17.5 \cdot 10^6 = 830 \cdot g \cdot x + 1000 \cdot g \cdot(2000-x) [/tex]
     
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