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Homework Help: Need help with Bouyant Force question

  1. Nov 9, 2009 #1
    1. The problem statement, all variables and given/known data
    Suppose that you release a small ball from rest at a depth of 0.600 m below the surface in a pool of water. If the density of the ball is 0.300 that of water and if the drag force on the ball from the water is negligible, how high above the water surface will the ball shoot as it emerges from the water? (Neglect any transfer of energy to the splashing and waves produced by the emerging ball.)

    2. Relevant equations
    F(b) = m(f)g (f is for fluid) - in this case water

    3. The attempt at a solution
    No idea how to set it up!
  2. jcsd
  3. Nov 9, 2009 #2


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    Gold Member

    It would probably be helpful to think in terms of energy when doing this problem: The work required to push the ball to a depth of 0.6m should equal the gravitational potential energy that it acquires when you release it.
  4. Nov 21, 2009 #3
    Humans are made mostly of http://www.ionizerscompared.com" [Broken] and are thus very close to being neutrally buoyant. However, if you take a large breath and hold it you can become positively buoyant since your overall volume increases thus lowering you overall density. Fat cells are less dense than water so people who carry a lot of extra fat can float more easily.
    Last edited by a moderator: May 4, 2017
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