Principia confusing sentence. Please make is simpler

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Discussion Overview

The discussion revolves around a complex sentence from Newton's "Principia" regarding the relationship between weights and torques in a mechanical system. Participants seek clarification on the meaning and implications of the sentence, which involves ratios and distances related to the pivot point of a wheel.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion over the meaning of a specific sentence from "Principia" and requests help in understanding it.
  • Another participant suggests that the sentence is primarily discussing torques.
  • A different participant emphasizes the importance of a diagram to understand the text, explaining that the "reciprocal ratio of the least distances of the chords" relates to the distances from the pivot point and how they affect torque.
  • Some participants acknowledge that while the language is complex, the underlying concepts can be grasped with the right visual aids.
  • There is a light-hearted comment about the continued relevance of "Principia" compared to other texts.
  • One participant suggests that the original text may not be the best choice for learning physics due to its complexity.

Areas of Agreement / Disagreement

Participants generally agree that the sentence is difficult to understand and that visual aids are helpful. However, there is no consensus on the clarity of the original text or its suitability as a learning resource.

Contextual Notes

The discussion highlights the challenges posed by the historical language and complexity of Newton's writing, which may obscure the underlying physical concepts for modern readers.

sabanation12
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Can someone please help me understand what this means?:

"And therefore if weight 'p' is to weight 'A' in a ratio compounded of the reciprocal ratio of the least distances of the chords PN, AM, from the center of the wheel, and of the direct ratio of pH to pN, the weights will have the same effect towards moving the wheel and will therefore sustain each other."

I am totally confused.

Tell me if this is insufficient to answer my question.

Thanks for any responses.
 
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Looks like he's just talking about torques.
 
People have to see the diagram to follow what's being said, but it actually very trivial. Look at the diagram when he says "a ratio compounded of the reciprocal ratio of the least distances of the chords". Old English sucks but the ratio is the weights p and A. The "chords" are the distances from pivot point at O. "Compounded of the reciprocal ratio" refers to the effects the chord lengths has on the weights relative torque.

It's really a mess but if you look at the picture and understand that O is a pivot point with weights hanging from the chords at some distance, and understand the forces it entails at various points, then it's obvious a lot of words was thrown at very little.
 
Ok, thanks guys. Even if I don't understand every last detail, I understand the broad idea of what he is talking about
 
People still read the Principia?

Well still better than reading the bible :)
 
sabanation12 said:
Ok, thanks guys. Even if I don't understand every last detail, I understand the broad idea of what he is talking about

It sounds as though this was your first choice for a physics textbook, while this isn't why you made the thread I would suggest that you find something else. There are many books that will give you more information more clearly.
 

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