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Homework Help: Find the speed of fluid using bernoulli

  1. Mar 25, 2012 #1
    1. The problem statement, all variables and given/known data

    Find v

    2. Relevant equations

    3. The attempt at a solution
    Here's what I've done

    I took the surface of water as first reference and the right-end of the pipe as second reference, so:

    P1 + 1/2 ρV12 + ρgh1 = P2 + 1/2 ρV22 + ρgh2

    P1 = P2 = Patm and I assumed v1 = 0 and h1 = 0, then the equation became:
    0 = 1/2 ρV2 - ρgh
    v = √(2gh) ---> ta daa, I'm finished with degree of confidence 0.5 % that my answer is correct.

    Do I get it right? Thanks
  2. jcsd
  3. Mar 25, 2012 #2
    It is 100% correct.

    However to build up your confidence lets just clear up how we got here.

    After applying the equations, we realised two things.Pressure at surface and Pressure at exit are same as they are open to atmosphere.

    Then we made velocity zero.
    That was using equation of continuity as surface area of water is much greater than that of pipe.
  4. Mar 25, 2012 #3
    Ah I get it. Thanks for the help :smile:
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