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Shape of lumps

  1. Sep 1, 2015 #1
    I was solving for a shape on earth which has minimum potential energy. i used method of variation calculus.
    I assumed a function f(x) and rotated it around Y axis. sorry for uploading the problem in word.

    Attached Files:

  2. jcsd
  3. Sep 1, 2015 #2


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    What direction does gravity point in?
  4. Sep 4, 2015 #3
    along negative y direction
  5. Sep 4, 2015 #4


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    I was hoping it would be enough of a hint for you.

    Gravity points towards the centre of the mass, not in the y direction. So as you go along the surface the direction of gravity changes.

    In other words, you have the wrong formula.

    Also, check your formula for potential energy.
  6. Sep 4, 2015 #5
    That shape will be a thin layer spread on the surface. Unless you consider some material going in holes under the surface.
  7. Sep 6, 2015 #6
    Dear DEvens
    i assumed a random curve so how to find the center of mass if i don't know in what geometry the mass is distributed
  8. Sep 6, 2015 #7
    i am sorry i understood what u meant i will workout the problem and let u know the answer.
    thanks for u help
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