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Homework Help: Sphere submerged in water

  1. Dec 8, 2008 #1
    1. The problem statement, all variables and given/known data

    A sphere completely submerged in water is tethered to the bottom with a string.?
    The tension in the string is one-third the weight of the sphere. What is the density of the sphere?

    2. Relevant equations

    3. The attempt at a solution

    Fnet = 0 = Fb-T- mg

    T=(Density of water x Volume of water x gravity) - (density of sphere x Volume of sphere x gravity)

    T= (denisty of water - density of sphere) (Volume of object)(Gravity)

    where volume of water = volume of sphere is completely submeged object

    Not sure what to do now

    Please help
  2. jcsd
  3. Dec 8, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You are told what T is, so substitute what T is into that equation.

    What's the buoyant force equal?

    Hint: You want to rearrange the equation to solve for density, which is m/V.
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