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Need to find WORK

  1. Feb 3, 2009 #1
    Find the work done in emptying a tank containing oil if the tank is hemisphere with a diameter of 6 feet. The tank is full and the density of the oil is 50lb/ft^3. The oil is raised to a point 4 ft about the top of the tank. Thank you for helping. I have no idea how to start.
  2. jcsd
  3. Feb 3, 2009 #2


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    Hi idle_09! :smile:
    (i assume you mean "4 ft above …"?)

    work done = change in energy (that's the work-energy theorem) …

    so divide the tank into horizontal slices of thickness dz, calculate the mass of each slice, how much energy is needed to raise it to z = 7, and integrate over z. :wink:
  4. Feb 3, 2009 #3
    you'll have to find the size of a slice of the hemisphere as a function of z... just figured I'd throw that hint out there.
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