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Homework Help: Simple Fluid Mechanics

  1. Mar 22, 2010 #1
    A circular pipe has a fall of 4m and narrows so that, at exit, its area is one quarter that at inlet. The pressure at inlet is 20kN/m^2 above atmospheric and at exit, where the velocity is 15m/s, the pressure is atmospheric.

    Calculate the inlet velocity and mass flow rate of water through the pipe per unit cross-sectional area at inlet.

    Relevant Equations: Bernoullis

    I've got this so far (if it is correct!):

    4 + (20 x 10³)/10³ x g + V²/2g = 15²/2g + h

    I'm not sure how to use the area values given to find out the velocity .. I presume I need to use Q = AV?
  2. jcsd
  3. Mar 22, 2010 #2
    Continuity equation:
    [tex]A_{1}v_{1} = A_{2}v_{2}[/tex]

    And Bernoulli is all you need.
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