Force Resultant is equal to the sum of the components -- why?

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Discussion Overview

The discussion centers around the question of why the resultant's X and Y components of two forces are equal to the sum of the X and Y components of those forces. It touches on theoretical aspects of vector addition and principles in classical mechanics.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants assert that the equality of the resultant's components follows from the addition laws of a vector space, suggesting a mathematical basis for the claim.
  • Others reference the geometric interpretation of vector addition, indicating that the visual representation of vectors supports this equality.
  • A participant mentions the Principle of Superposition as a foundational axiom in classical mechanics that underpins this relationship.
  • There is a question posed about the implications of adding another force, indicating a potential shift in the dynamics of the system, though it does not directly address the original question.
  • Another participant questions the nature of the forces involved, asking whether they pertain to pulling or pushing, which introduces ambiguity into the discussion.

Areas of Agreement / Disagreement

Participants express varying perspectives on the foundational principles behind the equality of the components, with some agreeing on the mathematical and geometric interpretations while others introduce different considerations. The discussion remains unresolved regarding the implications of additional forces and the nature of the forces in question.

Contextual Notes

Some assumptions about the nature of forces and the context of their application are not explicitly stated, which may affect the interpretations of the principles discussed.

Bassel AbdulSabour
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Why are the resultant's X and Y components of two forces equal the sum of the X and Y components of the two forces?
 
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Bassel AbdulSabour said:
Why are the resultant's X and Y components of two forces equal the sum of the X and Y components of the two forces?
Why not? What else would they be equal to?
 
Bassel AbdulSabour said:
Why are the resultant's X and Y components of two forces equal the sum of the X and Y components of the two forces?
Because these are the addition laws of a vector space: ##\begin{bmatrix}u_x\\u_y\end{bmatrix}+\begin{bmatrix}v_x\\v_y\end{bmatrix}=\begin{bmatrix}(u+v)_x\\(u+v)_y\end{bmatrix}\,.## This coincides with the geometric vector addition of arrows. But whatever you take as a definition, they should yield the same result.
 
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upload_2018-9-19_18-13-19.jpeg


If one more person was added to the right end of the rope, which side would win?
 

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Pulling or pushing ?
 
Bassel AbdulSabour said:
Why are the resultant's X and Y components of two forces equal the sum of the X and Y components of the two forces?
It follows from one of the axioms of Classical mech.: the Principle of Superposition
 

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