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Homework Help: Piston Pressure

  1. Dec 15, 2009 #1
    1. The problem statement, all variables and given/known data

    A piston can move without friction inside a large tube of .002m^2 of cross sectional area. The weight of the piston is negligible. A mass of kg sits on top of the piston as shown in the figure below. The large tube is connected to a horizontal smaller tube which has 4 x 10^-6 m^2 of cross sectional area. the end of the small tube is open to atmosphere. the piston is moving down at a speed of v = .02 m/s. both of the tubes are filled by water and the density of water is 1000 kg/m^3. Assume frictions and the viscosity of water to be negligible.

    A) Find the flow speed of water at the end of the small tube as the water exits to the atmosphere.

    We went through a very similar example in class, where the professor used the formula 1/2mv^2=mgh to solve the problem.

    However, on this problem the height is not given and I was unsure how to continue to solve the problem.

    B) Find the height of the piston from the center of the small tube.

    Well if I could figure out part A, I could put velocity into the equation 1/2mv^2=mgh and solve for h.

    If anyone could guide me towards what equations to use, that would be awesome.

    Last edited: Dec 15, 2009
  2. jcsd
  3. Dec 15, 2009 #2
  4. Dec 15, 2009 #3
    Patience, young Skywalker.
  5. Dec 15, 2009 #4
  6. Dec 15, 2009 #5
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