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How can I calculate h from this diagram

  1. Dec 5, 2014 #1
    • Member warned about not using the homework template
    aNbzApR.jpg
    Water flows in the horizontal pipe shown in Fig. 13-6. At A the area is f1064g1q1g1.gif and the speed of the water is f1064g1q1g2.gif At B the area is 16.0 cm2. The fluid in the manometer is mercury, which has a density of f1064g1q1g3.gif What is the manometer reading h?

    My attempt:
    I used A1V1 = A2V2 to find the speed at B which is 3.125
    Then I used Bernoulli equation and I have: P(A) = P(B) + 2883
     
    Last edited by a moderator: Apr 18, 2017
  2. jcsd
  3. Dec 5, 2014 #2

    gneill

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    Staff: Mentor

    In future, please retain and use the formatting template provided when you start a thread in the homework areas.

    Assuming that you have the correct pressure difference between A and B then if you assume some cross-sectional area for the mercury tubing you should be able to assign forces at the mercury surfaces. Since the mercury is in equilibrium, something needs to balance out the forces applied at the surfaces...
     
    Last edited: Dec 5, 2014
  4. Dec 5, 2014 #3

    Mark44

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    Noted and addressed.
     
    Last edited: Dec 5, 2014
  5. Dec 5, 2014 #4

    hey, can you please elaborate.
    p(a) is applied on left side and on right side p (a) - 2883 but what is the next step?
     
  6. Dec 5, 2014 #5

    gneill

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    Staff: Mentor

    What might cause a change in pressure with height (or depth) in a fluid?
     
  7. Dec 6, 2014 #6

    rude man

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    Homework Helper
    Gold Member

    You know p1 - p2. Just apply Bernoulli again for the mercury in the U-tube. (You don't need to know the area of either side of the tube; in fact, they can be very different.)
     
    Last edited: Dec 6, 2014
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