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The period of water oscillating in a U-tube

  1. Jan 31, 2012 #1
    In the following lecture (starting at 21:00), the professor says that when predicting the period of water oscillating in a U-shaped tube, that the "length" of the water column that you should use should be greater than the average of the length around the outside and around the inside. Can someone explain this? Thanks.
    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Feb 1, 2012 #2
    The length is used to calculate the volume of the water, and the volume is used to calculate the kinetic energy of the water if it's moving with a speed v.

    The water on the outside will be moving faster than the water on the inside, and because the kinetic enegy depends on the square of the speed, the sum won't add up to the kinetic energy of the water in the middle.
  4. Feb 1, 2012 #3
    Great explanation. Thanks.
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