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Water flow in pipes

  1. Apr 6, 2008 #1
    [SOLVED] Water flow in pipes

    1. The problem statement, all variables and given/known data
    Water is circulating through a closed system of pipes in a two floor apartment. On the first floor, the water has a gauge pressure of 3.4 x 10^5 Pa and a speed of 2.1 m/s. However, on the second floor, which is 4.0m higher, the speed of the water is 3.7m/s. The speeds are different because the pipe diameters are different. What is the gauge pressure of the water on the second floor?

    2. Relevant equations
    A1V1 = A2V2

    P1 - .5(rho)(v1)^2 + (rho)gy1 = P2 + .5(rho)gy2

    Efinal = Einitial
    KEfinal + PE final = KEinitial + PE initial

    Wnc = E1 - E2 = (.5mv1^2 + mgy1) - (.5mv2^2 + mgy2)

    3. The attempt at a solution
    Last edited: Apr 6, 2008
  2. jcsd
  3. Apr 6, 2008 #2
    Use Bernoulli's equation to solve it. You have what you need.
  4. Apr 6, 2008 #3
    It doesn't matter that the Area changes?..also, I don't know what rho is? do I just use the standard rho of water?
  5. Apr 6, 2008 #4
    They've already given you all the information you need. If they asked "find the area of the upper tube" then you would care about the fact that the two velocities are different.
  6. Apr 6, 2008 #5
    what about rho though?
  7. Apr 6, 2008 #6
    You know, or should know, the density of water.
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