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Velocity in a pipe

  1. Aug 27, 2014 #1
    I need to find the velocity within a pipe , I know the flow rate and diameter

    Flow rate =0.01
    Diameter =90mm

    Am I correct in thinking to use V =Q/A

    Where A is found using A=pi/4 x D^2

    Using this I got A =0.0064m but somehow this does not seem quite right to me

    Can anybody please tell me where I am going wrong please

  2. jcsd
  3. Aug 27, 2014 #2


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    Please include units for all quantities. How else can we tell what these numbers mean?
  4. Aug 27, 2014 #3
    0.01m3 s-1
  5. Aug 27, 2014 #4


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    Yes, it's not quite right. Your answer is a length...you want an area.
  6. Aug 27, 2014 #5
    Ah so it should be m^2 ?
  7. Sep 1, 2014 #6
    What are the units for your flow rate?

    And also, Your equation for area includes the term D^2 which implies the diameter is being squared, so your answer for area should have the units mm^2.
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