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Pressures on a tube filled with water

  1. Jan 13, 2007 #1
    1. The problem statement, all variables and given/known data

    I'm stuck on a problem. If you have a 1'' diameter tube running vertically about 7 feet in the air and 5 feet of the tube was full of water. And at the top of the tube was closed off. And the 2 feet above the water had a vacuum pressure of negative 1 psi.(I don't know vacuum measurements so I put it as a negative psi) Would the water rise upward to the vacuum area. or because the water would have a downward pressure of 3 psi would the water level remain the same.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jan 14, 2007 #2
    I'm just wondering because I know if you want to rise water around 34 feet in the air you would have to have a suction force of around 14 psi. Then the water pressure equals the atmospheric pressure. But if you have lets say a bowl of water with a 7 foot pipe running vertically and if the water in the pipe is at 5 feet. It would have a downward force of 3 psi. Now if you had a low vacuum in the pipe, less than 3 psi worth. Would the water rise because of the atmosperic pressure pushing the water upward. Or would the vacuum force be too weak to affect the water.
  4. Jan 15, 2007 #3
    Does anyone know the answer to my question.
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