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Homework Help: Fluid/Stream Que! work shown! need guidance!

  1. Jan 25, 2009 #1
    1. The problem statement, all variables and given/known data
    A can is filled with water to a depth of 37cm. A hole 12 cm above the obttom of the can produces a stream that is directed at a 34 degree angle ave the horizontal. Find the range and max height of this stream.

    2. Relevant equations
    by kinetcs

    3. The attempt at a solution.

    =sqrt 2x9.81x (0.37m-0.12m)
    = 2.21m/s

    using the angles to get the vertical velocity: 2.21m/sxsin34=1.26m/s

    I then use the eqn vf^2=vi^2+2ad where a=g
    ultimately getting 7.8cm which I add to the 12cm to get approx 20cm as max height

    as for the range, am i able to use the same velocity except with the x-component velocity?

    Anyways, I'm slightly confused now. Thanks for any help!
    Last edited: Jan 25, 2009
  2. jcsd
  3. Jan 26, 2009 #2


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    Science Advisor
    Homework Helper

    jen333: Generally always maintain four significant digits throughout all your intermediate calculations, then round only the final answer to three significant digits. Your stream maximum height looks correct, y2 = 19.82 cm. You are doing quite well, so far, except for a minor typographic mistake; the stream initial vertical velocity, neglecting exit minor head loss, would be v1y = v1*sin(theta) = (2.214 m/s)sin(34 deg) = 1.238 m/s. Yes, you would use the same stream initial velocity, v1, to compute the stream horizontal velocity, vx. Next, use one of your kinematics equations to compute the stream final vertical velocity, v3y, when the stream hits the ground. Hopefully this will get you started. Continue using the kinematics equations to solve the problem.
  4. May 17, 2011 #3
    The x component of the velocity is already there: the x component is constante Vx=Vo*cos(angle), and it eqaution of the motion can be found easily: X=Vx(t)+Vo.
    in terms of stream function you can use dy/dx=Vy/Vx
  5. May 17, 2011 #4
    Also in this kind of problems you can use the Lagrangain concept, you don't need the Eulerian concept. but for the mass flow rate and so on you, need to use the principe of the conservation of mass.the continuity equation
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