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Homework Help: Archimedies Principle

  1. Nov 22, 2007 #1
    Archimedies Principle!!!!!

    1. The problem statement, all variables and given/known data

    Hot air balloon question. We are not given the density nor are we able to look it up.
    cold air is 278K, hot air is 313K
    radius of balloon = 10
    What is its payload capabilities?!

    2. Relevant equations

    payload = mass of cold air - mass of hot air
    P1V1/T1 = P2V2/T2

    3. The attempt at a solution

    P1 = 101 kpa which i think is a constant
    P2 = P1x(T2/T1)
    = 101x(313/278)
    =113.7 kpa

    working this into the pV = nRT is where the trouble is
  2. jcsd
  3. Nov 22, 2007 #2
    Fill in n=m/M?

    You know V, T. So you can calculate m. For M you have O2 and N2 in the air. Use Mendeljev.
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