Is Normal Force a Contact Force Despite Atomic Repulsion?

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Discussion Overview

The discussion revolves around the nature of normal force and whether it qualifies as a contact force, particularly in the context of atomic repulsion. Participants explore the implications of atomic interactions on the concept of contact forces, including normal force, tension, and friction.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that normal force is considered a contact force, but question whether two objects are truly touching or if there is a minuscule space between them.
  • One participant suggests that if objects are close enough for contact forces to exist, they can be considered "touching," although there may be a small non-zero range for contact forces.
  • Another participant explains that normal forces, along with other contact forces, are part of electromagnetic forces and highlight that at the atomic scale, objects do not actually touch due to electron repulsion, but can be treated as touching on a macroscopic scale.
  • A participant requests clarification on the "technical" definition of touching, indicating a desire for a more precise understanding of the concept.

Areas of Agreement / Disagreement

Participants express differing views on the definition of contact and touching, with no consensus reached on the implications of atomic repulsion for the classification of normal force as a contact force.

Contextual Notes

The discussion highlights limitations in defining "touching" and the assumptions regarding the scale at which forces operate, particularly the distinction between atomic and macroscopic interactions.

Physics4Eva
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Guys I was just wondering if normal force is a contact force. Obviously it is considered a contact force but it also has something to do with the repelling of atoms. In my mind, normal force is a fundamental truth, but technically, are two objects touching or is there a minuscule space between the object.
 
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Physics4Eva said:
Guys I was just wondering if normal force is a contact force.
Yes.

Physics4Eva said:
are two objects touching or is there a minuscule space between the object
If they are close enough for contact forces to exist then they are “touching”. It may be that contact forces have some small non zero range.
 
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Thanks for the quick reply:wink:
 
Normal forces, and other so-called contact forces like tension and friction forces, belong to the family of forces called electro-magnetic forces (as distinguished from the strong and weak nuclear forces, and the ‘action at a distance’ classical gravity “force”). Being an electromagnetic force, contact forces actually never touch each other on the atomic scale, due to the repulsion of electrons between the objects in contact. For all practical purposes however, they can be considered as touching on the macroscopic scale.
 
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Very intuitive😜
 
Physics4Eva said:
... but technically, are two objects touching ...
What is your "technical" definition of touching?

 
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