Heavy question; the gravity of a thought experiment

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Discussion Overview

The discussion revolves around the effects of surrounding geological features on gravitational forces, specifically in the context of a thought experiment involving a ferris wheel positioned over a cliff. Participants explore whether the differing gravitational influences on the wheel's buckets could induce motion or spinning due to the uneven distribution of mass beneath them.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant, Mitch, questions whether the gravitational pull on a ferris wheel would differ enough on either side of a cliff to cause it to spin, given that one side has no Earth beneath it.
  • Another participant notes that local gravitational fields can vary based on the density of underground rock formations, referencing historical applications in mining, but suggests that such variations would not be significant enough to affect a ferris wheel noticeably.
  • A different viewpoint emphasizes that gravity acts in all directions, implying that the gravitational pull from the ground beneath the ferris wheel would still affect the entire structure uniformly.
  • One participant asserts that energy conservation principles dictate that lifting and dropping a bucket would require the same amount of energy, regardless of the path taken, suggesting that the configuration of the ferris wheel does not influence gravitational effects.
  • Another participant argues that no side of the wheel would experience a greater gravitational attraction, leading to the conclusion that the wheel would not spin as a result of the cliff's presence.

Areas of Agreement / Disagreement

Participants express differing views on whether the gravitational effects due to the cliff would cause the ferris wheel to spin. While some argue that gravitational forces would be uniform, others explore the implications of local geological variations, indicating that the discussion remains unresolved.

Contextual Notes

Participants have not provided specific mathematical analyses or detailed calculations to support their claims, leaving the discussion open to interpretation and further exploration of the underlying assumptions regarding gravitational effects.

mjhilger
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Just thinking about gravity. How is the gravity effected by the surroundings of a location?

Suppose we have a giant farris wheel with very good bearings and we place it in a location; like the Grand Canyon - somewhere with a very steep dropoff; such that say 40% of the wheel is over the cliff. So the buckets that cross the boundary of the cliff have no Earth below them for say 2500 feet at least; while the other side is positioned over solid rock/earth. Would there be a large enough difference in the delta of the gravity to cause a spin from the buckets over the solid Earth having more pull? I have not worked out the math yet, just a ponder?

Thanks,
Mitch
 
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The local gravitational field varies with the density of local/underground rock formations. Mining companies have been using this information as part of their scientific prospecting technique since Eötvös developed practical devices. See the Wikipedia article on Eötvös.

But is it enough to move something besides the most delicate of balances? The answer is not so that anybody would notice.
 
Gravity doesn't just pull in one direction, it pulls in all directions. So you can't prevent the ground underneath the ferris wheel from pulling on the entire ferris wheel.
 
Of course not. Energy is conserved. It takes as much energy to lift a bucket as you get from dropping a bucket. It doesn't matter if you lift it in some zig-zag direction or straight up.
 
No one side of the wheel would be attracted more than the other, so it would just stop.
Say it was a very sensitive beam balance hanging over the cliff with equal weights one end would go down and the other up and then stay there what makes you imagine it would spin.
 

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