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Homework Help: Tarzan, Fluids, and Pressure

  1. Jan 18, 2005 #1
    Ape Man in a movie is shown evading his captors by hiding underwater for many minutes while breathing through a long reed. Assuming the maximum pressure difference lungs can manage and still breathe is -80 mm-Hg , calculate the deepest he could have been.

    I immediately thought of P = p*g*h, where p = density. h is the depth, but this is for gauge pressure. Do I use the formula for absolute pressure P = atmospheric pressure + pgh?

    Am I correct in my reasoning?

  2. jcsd
  3. Jan 18, 2005 #2
    First... you have to make an assumtion that the lung won't be compress under water, otherwise the problem can't be solve this way.
    Yes the absolute pressure under water is [itex] \rho g h + 1atm [/itex]... however, the pressure inside the (uncompressed) lung is 1atm... so the DIFFERENT of the pressue is [itex] \rho g h[/itex]
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