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Homework Help: Helium-filled balloon tied to mass

  1. Nov 21, 2009 #1
    1. A 1.10 balloon is filled with helium gas until it becomes a 24.0 -diameter sphere. What maximum mass can be tied to the balloon (with a massless string) without the balloon sinking to the floor? (in grams)

    2. F = ma
    pA = p*pi*r^2

    3. radius = 0.12m

    F_air = p*pi*r^2 = 4583N, assuming 1atm pressure i.e. 101,300Pa

    F_air = mg

    m= F_air / g = 467000 grams
  2. jcsd
  3. Nov 21, 2009 #2
    I assume this is the wrong approach?
  4. Nov 21, 2009 #3
    Nevermind, I got it.
  5. Nov 21, 2009 #4
    What's Archimedes' buoyant force?
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