Finding Min. Potential Energy: Variation Calculus Method

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Discussion Overview

The discussion revolves around finding the shape on Earth that minimizes potential energy using the method of variation calculus. Participants explore the implications of gravity's direction and the assumptions made regarding the distribution of mass.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant describes their approach to solving for a shape with minimum potential energy by using variation calculus and rotating a function around the Y-axis.
  • Another participant questions the direction of gravity, suggesting it points towards the center of mass rather than strictly in the negative y-direction.
  • A participant emphasizes the need to check the formula for potential energy, implying that the initial assumptions may be incorrect.
  • There is a mention of the shape being a thin layer on the surface, with a consideration of how material might interact with subsurface areas.
  • One participant expresses uncertainty about finding the center of mass due to the random nature of the assumed curve and the unknown geometry of mass distribution.
  • A later reply indicates a willingness to revisit the problem after understanding the previous comments, suggesting ongoing engagement with the topic.

Areas of Agreement / Disagreement

Participants express differing views on the direction of gravity and the implications for the potential energy formula. The discussion remains unresolved, with multiple competing perspectives on the assumptions and methods used.

Contextual Notes

There are limitations regarding the assumptions made about the geometry of mass distribution and the potential energy formula, which have not been fully clarified or resolved.

Gayle
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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.
 

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What direction does gravity point in?
 
along negative y direction
 
Gayle said:
along negative y direction

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.
 
That shape will be a thin layer spread on the surface. Unless you consider some material going in holes under the surface.
 
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
 
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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