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Homework Help: Buoyant force of an aluminum block

  1. Apr 17, 2012 #1
    1. The problem statement, all variables and given/known data

    An aluminum block has a mass of 0.25kg and a density of 2700 kg/m cubic.

    a) calculate the volume of the aluminum block.
    b) Determine the buoyant force exerted on this block when it´s completely submerged in water of density 1000kg/m cubic.

    2. Relevant equations

    v = m/d

    3. The attempt at a solution

    I already solved for a and I got:

    v = 0.25/2700 = 9.25 x 10 to the power of -5

    Now for b), I am not sure... i did something like:

    9.25 x 10-5 x 1000 x 10
    9.25 x 10-5 x 1.0 to the power of 3 x 10
    9.25 x 10-1 ?
    Last edited: Apr 17, 2012
  2. jcsd
  3. Apr 17, 2012 #2

    Doc Al

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    Staff: Mentor

    OK. (But don't leave out the units.)

    If the block were submerged in water, that would be about right. (Using g = 10 m/s2.) (Again, don't leave out the units.)
  4. Apr 17, 2012 #3
    Why do i have someone saying the answer should be 92.5 for a) ?
    Last edited: Apr 17, 2012
  5. Apr 18, 2012 #4

    Doc Al

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    Staff: Mentor

    They are expressing the volume in cm3 instead of m3.
    Last edited: Apr 18, 2012
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