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Homework Help: Help on pressure !

  1. Oct 25, 2007 #1
    help//// on pressure.... !

    1. The problem statement, all variables and given/known dataWhat gauge pressure in the water mains is necessary if a firehose is to spray water to a height of 20 ?

    2. Relevant equations
    Pressure = density * gravity * chanfe of height

    3. The attempt at a solution

    density of the water is 100 kg/m^3
    so will the solution be:
    100 (kg.^3) * 9.8 (m/s^2)* 20m
    =19600 pa????
  2. jcsd
  3. Oct 25, 2007 #2


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    Homework Helper

    To determine the gauge pressure inside a hose pipe you have to apply Bernoulli's principle. Inside the pipe the pressure is P and velocity of flow of water is zero. Outside the pipe pressure is ane atmosphere
    = 1.013*10^5 pa. Find the velocity of projection of any body to reach the height h.Use the equation P + 0 = 1.013x10^5 + 1/2xdensity waterxv^2. Density water is 1000kg/m^3
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