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Homework Help: Bernoulli Principle

  1. Dec 3, 2012 #1
    1. The problem statement, all variables and given/known data

    Water Flows upward throw the pipe shown in the diagram at 96 L/Min. If the pressure at the lower end is 80kPa, find the velocity of the water is at both ends and the pressure at the upper end. Assume that the density of water remains constant throughout the tube and that h1= 10 m and h2 = 13m

    2. Relevant equations
    P1+ 1/2 ρv^2+gy1=P2+1/2ρv2^2+gy2

    Continuity Equ:
    (Tried to use this equation to hep me find the velocity but given their is no diameter or radius given to find the are it was a waste of time)

    3. The attempt at a solution
    volume flow rate up the pipe:
    96L/min (1.0X10^3 cm^3/ 1.00L)(1.00m/100cm)^3(1.00min/60sec) = 1.6x10^3 m^3/s

    Attempt to tried to use the Continuity Equation as substitution for one of the velocities:


    V2(A2/A1)= V1

    Substituting V1 in the Bernoulli Equation:


    sqrt(2gh)/sqrt(1-(A2/A1)^2) =v2

    Any help or guidance will be appreciated. Thank you.
  2. jcsd
  3. Dec 3, 2012 #2


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    Science Advisor
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    Gold Member

    Something missing in the problem statement?
    Should be ρgy1, ρgy2, yes?
    It doesn't mention any change in area, so presumably A1=A2.
    How do you get that last equation from the preceding one? What happened to P1 and P2?
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