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Homework Help: Drawing lemonade of density 1000 kg/m3 up a straw to a maximum height

  1. Nov 3, 2006 #1
    To suck lemonade of density 1000 kg/m3 up a straw to a maximum height of 3.3 cm, what minimum gauge pressure (in atmospheres) must you produce in your lungs?

    I know i need to use P=pgh which equals 1000(9.81)(.033)
    which equals 323.73
    -Then i divide, so, 323.73/1.0125e5
    that equals 3.197e-3

    It said that my answer was wrong. It looks good to me. Thanks for the help.
     
  2. jcsd
  3. Nov 3, 2006 #2

    berkeman

    User Avatar

    Staff: Mentor

    What's the conversion you are using from mks units to atmospheres?
     
  4. Nov 3, 2006 #3
    You're answer better be negative.
     
  5. Nov 3, 2006 #4
    thanks man, it was negative.
     
  6. Jan 15, 2009 #5
    Re: Fluids

    I just did this problem and was wondering why the answer was negative? How often can pressure be considered negative?

    Thanks for the help!

    ~Phoenix
     
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