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Homework Help: Buoyant Force Problem

  1. Apr 15, 2008 #1
    1. The problem statement, all variables and given/known data

    The tallest iceberg ever measured stood 167 m above the water. Suppose that both the top and the bottom of this iceberg were flat and the thickness of the submerged part was estimated to be 1.50 km. Calculate the density of ice. The density of sea water equals 1025 kg/m3.

    2. Relevant equations

    Weight of the object / Buoyant Force = Density of the object / Fluid density
    V = L x W x H
    Density of fluid / density of object = volume of object / volume of fluid

    3. The attempt at a solution

    I don't want an answer, I just need help figuring out how I'm supposed to find the volume.
    I know that I need the volume in order to find the density, and the mass...but how do I find either the density OR volume with just the height and the submerged height? I know that I'm supposed to assume the iceberg is a rectangular prism...but shouldn't I know the mass or volume in order to find the density?
    How do you find the volume with only the height?
  2. jcsd
  3. Apr 15, 2008 #2


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    Homework Helper

    You don't need to know the mass. You are assuming it is a rectangular box, not a prism. So the length and width are the same for the volumes of the iceberg above and below the water.

    The second equation you listed is all that is really needed.
  4. Apr 15, 2008 #3
    But how do you find the volume with only a height? I don't know the length and width...
  5. Apr 15, 2008 #4


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    Homework Helper

    You can still express the volumes you need in terms of L,W,H by just using the variables and put them into the equation. You don't need to know L and W directly. They will be cancelled out.
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