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Homework Help: A nurse using a syringe

  1. Jun 12, 2009 #1
    1. The problem statement, all variables and given/known data
    A 1.63 mL syringe has an inner diameter of 5.04 mm, a needle inner diameter 0.21 mm, and a plunger pad diameter (where you place your finger) of 1.06 cm. A nurse uses the syringe to inject medicine into a patient whose blood pressure is 140/100. What is the minimum force the nurse needs to apply to the syringe?

    2. Relevant equations


    3. The attempt at a solution
    I understand that the pressure is constant through out the syringe, but what I don't know how the blood pressure is used. I see that i can use blood pressure=force/(area of needle inner diameter) solve for force. then use the relationship F/A to solve for the tap.

    So long story short......does it matter what the blood pressure number is or do i have to change it to Pa/atm some how?
  2. jcsd
  3. Jun 12, 2009 #2
    im so confused about the blood pressure thing. FML
  4. Jun 12, 2009 #3
    Blood pressure is unit force per area, so is that just mean im left with F1/A1=Blood pressure
  5. Jun 12, 2009 #4


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    Homework Helper

    What is the pressure needed to get the goodies to enter the blood stream?

    Blood pressure is measured in mmHg if that is the clue you need.
  6. Jun 15, 2009 #5
    oh thats i couldn't find, let me work knowing that and see if I can figure it out.
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