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Pressure - breathing through a reed

  1. Dec 19, 2006 #1
    I'm getting stumped by these questions..can someone please help me?

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

    1. In a movie, Tarzan evades his captors by hiding underwater for many minutes while breathing through a long, thin reed. Assuming the maximum pressure difference his lungs can manage and still breathe is 80.7 mmHg, calculate the deepest in cm that he could have been.

    2. The gauge pressure in each of the four tires of an automobile is 240 kPa. What is the actual pressure in each tire in psi?

    2. Relevant equations

    1. 760mmHg=33 ft. of water

    2. none

    3. The attempt at a solution

    1. I multiplied 80.7 by 33 and divided it by 760...than after that I converted it but I still get it wrong.

    2. I converted the kpa to psi... Isn't that all I need to do? I converted it but I got it wrong..
    Last edited: Dec 19, 2006
  2. jcsd
  3. Dec 19, 2006 #2

    Doc Al

    User Avatar

    Staff: Mentor

    That seems right to me. Show your calculation.

    You need to know the meaning of "gauge pressure". Read this: http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html#c5"
    Last edited by a moderator: Apr 22, 2017
  4. Dec 19, 2006 #3



    that is the wrong answer...
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