Is there anything more to forces than being mathematical machinery?

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Discussion Overview

The discussion revolves around the nature of forces in physics, questioning whether they represent physical realities or are merely mathematical constructs. Participants explore the implications of defining forces, their role in classical mechanics, and the challenges in understanding their fundamental essence.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants argue that forces are simply a means to calculate motion between interacting bodies, suggesting that the concept may not have a physical underpinning beyond mathematical abstraction.
  • Others challenge the notion that forces lack a tangible definition, asserting that definitions are essential for understanding any concept, including force.
  • A participant highlights the difficulty in intuitively grasping what force is, contrasting it with other measurable vector quantities like position and velocity.
  • Historical perspectives are introduced, referencing Newton's skepticism about the nature of gravitational force and the lack of a mechanism for its transmission.
  • Some participants propose that the concept of force is motivated by practical experiences, such as the effort required to lift heavy objects, indicating a real-world basis for the abstraction.
  • There is a discussion about the abstraction of force being essential for its application across various scenarios, suggesting that it allows for flexibility in understanding interactions.
  • One participant mentions the complexities introduced by relativistic theories, hinting at the evolving nature of the definition of force in different contexts.
  • Concerns are raised regarding situations where opposing forces result in no acceleration, questioning the adequacy of the force definition in such cases.

Areas of Agreement / Disagreement

Participants express a range of views on the nature of forces, with no clear consensus reached. Some see forces as essential physical realities, while others view them as mathematical abstractions. The discussion remains unresolved regarding the fundamental essence of forces.

Contextual Notes

Participants acknowledge the limitations of definitions and the challenges in understanding forces without referring to established models. The discussion also touches on the historical context of force definitions and their implications in classical and relativistic physics.

  • #61
DrStupid said:
I usually refer to the original wording.
Not usually the best approach. The ideas have been polished and refined since Newton first stated them.
That means that forces are the only cause for changes in the state of motion of bodies. Frames of references are not even mentioned.
A more modern view is that cause and effect are irrelevant. If there is a change of momentum, there is a net force. If there is a net force, there is a change of momentum. The two concepts are not cause and effect -- they are more nearly synonymous. We adopt the definition that a "force" is a transfer of momentum and that an "inertial frame" is one in which Newton's first law holds good.
 
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  • #62
vanhees71 said:
Then the 2nd Law says that the causes of changes of the state of motion (the deviation from rectilinear uniform motion) are forces,
That’s what I believe and have found that same expression expressed by some other well known physicists (including you).
 
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  • #63
Adesh said:
some other well known physicists

You mean Newton? He's pretty well known, I guess. :wink:
 
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  • #64
etotheipi said:
You mean Newton? He's pretty well known, I guess. :wink:
Mr. Feynman, Mr. Arnold Sommerfeld and few others too.
 
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  • #65
DrStupid said:
According to N1 force is the cause and the change of motion the effect. How is this not a causality?
Science has ‘identified’ a common but rather slippery intermediate agency - a Force- which takes the place of all other real agencies: horses, falling water, a spring, a magnet etc.. The term Force allows us a common concept that can be treated a bit like money. We can earn money from many sources and spend it in many ways. Maths is what helps us deal with quantities involved. You could say that the causality is between the tennis player and the ball and the force just allows you to appreciate the quantities involved.
Our brains treat both forces and money as if they are real but they’re only in your head. I thing this justifies the OP and you can choose validly to look at things that way.
 
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  • #66
Since the OP has been answered and this thread is now veering off into a repetition of a discussion that was previously closed it is time to close this thread also.
 
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