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Homework Help: Atmospheric pressure in the higher tank

  1. Feb 27, 2007 #1
    1. The problem statement, all variables and given/known data
    If you had a tube running from the top of one tank at a lower level to the top of another tank at a higher level.
    And the water could only flow in one direction towards the higher tank.
    And the water level in the high tank started to descend.
    I think the tube would pull water up because of atmospheric pressure on the low tank pushing the water up.
    But what makes the water in the supply tube of the higher level tank descend?

    2. Relevant equations

    3. The attempt at a solution
    Wouldn't the atmospheric pressure in the higher tank transfer its pressure to the water in the tube. So the water in the supply tube is 14.7psi. the same pressure as the surface of the water in the tank.
    Or does gravitational potential energy play a factor
  2. jcsd
  3. Feb 27, 2007 #2
    What is the difference in the atmospheric pressure at the lower tank compared to that at the upper tank?
  4. Feb 27, 2007 #3
    I just thought that there would be other forces involved in forcing the fluid to move.
  5. Feb 27, 2007 #4
    I'm not saying that the only thing to consider is the atmospheric pressure. You brought it up, so I figured at least we could calculate the difference to see how significant that effect might be...
  6. Feb 27, 2007 #5
    Okay but if you have water in the supply tube at a higher level than the tank wouldn't the water want to move from higher elevation to lower elevation.
  7. Feb 27, 2007 #6
    This question is tricky depending on the details.
    The water should like to lower its P.E., yes.
  8. Feb 27, 2007 #7
    So would the need for the water to lower it P.E., would that allow the water to flow.
  9. Feb 27, 2007 #8
    Uncomplicated answer-yes.
  10. Feb 27, 2007 #9
    can you give me the complicated answer so I can understand it properly
  11. Feb 27, 2007 #10
    lol. What level class is this question from?
  12. Feb 27, 2007 #11
    Last question.
    Does the descending water in the tank give energy to the water in the supply tube.
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