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Homework Help: Lifting using air presure

  1. Feb 10, 2010 #1
    1. The problem statement, all variables and given/known data
    * A blue whale is spraying out air in a vertical column every time it exhales.
    * The whale is exhaling a volumn V[air] = 6 m^3 of air in every blow at an initial speed of v[air] = 30 m/s. (The velocity is a guess.)
    * The diameter of the whale's blowhole is d = 0,2 m.
    (I am not sure whether of not I need some additional imformation.)

    Question: How fare up in the air h will a person of mass m[person] = 54 kg be lifted if this person is sitting on the back of a blue whale, right on top of the blowhole when the animal exhales?


    2. Relevant equations
    * The masse of the air: m[air] = V[air]*density[air]. (The air's density is found in a physics encyclopedia or similar, I assume).

    * The presure of the air when leaving the whale p[air]. (I probably have to use the air's velocity and mass in some way.)
    * In should probably be able to calculate at what height a person of mass 54 kg will be lifted, given the "lifting" presure p[air].

    3. The attempt at a solution
    <See 2. for my attempt.>
    Also, I have taken a look at http://en.wikipedia.org/wiki/Fluid_statics for some inspiration but it did not give me anything.
     
  2. jcsd
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