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Homework Help: Water fountain - what power is expended to get it to a certain height?

  1. Oct 30, 2008 #1
    1. The problem statement, all variables and given/known data
    A fountain shoots a stream of water 10 m up in the air. The base of the stream is 10 cm across. What power is expended to send the water to this height?

    2. Relevant equations
    Power = change in work / change in time (Joules / second = Watts)
    x - x0 = v0t + 1/2at2
    v = v0 + at

    3. The attempt at a solution
    This question is from chapter 8 (Conservation of Energy) in the extended 3rd edition of "Physics for Engineers and Scientists". The Class is Physics with Calculus I. My professor gave this problem as one of the HW assignments, and we turned in the HW already, but he never goes over any of the questions. Just curious on how to get the answer. This is as far as I could go:
    Mass is not given.
    Velocity = sq rt of 2gh = 14.007 m/s.
    Volume = lwh = 0.1(10)w = w.
    Density = m/v = m/w. Density of water = 1000 kg/m3. Mass = dv = 1000w.
    Power = [mgh/t] = [1000w(9.81)(10) / t] = [98100w/t].
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 30, 2008 #2
    I got it. The answer is 10851.8 Watts.
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