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Homework Help: Change in pressure with fluids

  1. Nov 27, 2006 #1
    A garden hose with a diameter of 0.66 in has water flowing in it with a speed of 0.65 m/s and a pressure of 1.0 atmospheres. At the end of the hose is a nozzle with a diameter of 0.25 in.
    (a) Find the speed of water in the nozzle.
    (b) Find the pressure in the nozzle.

    I found out the speed of the water, but I am not sure how to find the pressure. I tried using the equation P1+1/2 pv1^2=P2+1/2 pv2^2 and solving for P2 but the answer that I get is negative. I think the problem is that I'm not sure about what to plug in for p. I looked up the density of water and used that value (1000), but am I supposed to figure it out another way? Because the only other equation I found for density was m/v and I wouldn't be able to calculate that.
  2. jcsd
  3. Nov 27, 2006 #2
    The pressure will come out of your equation. Don't forget that being on earth and having an atmosphere, we have an initial pressure.
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