Friction Independent of Area: Understand It Here

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Discussion Overview

The discussion revolves around the concept of friction, specifically whether it is independent of the area of surfaces in contact when the normal reaction remains constant. Participants explore the implications of this relationship and seek clarification on conflicting statements encountered in literature.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants assert that friction is independent of the area of contact as long as the normal reaction remains the same, referencing the standard model of friction (F = μN).
  • Others express confusion regarding the statement that friction could depend on area under certain conditions, questioning the validity of such claims.
  • A participant cites a book that suggests friction force is independent of area except when the normal reaction remains the same, prompting further inquiry into this assertion.
  • One participant points out that in specific scenarios, the area of contact can influence the normal reaction, thereby affecting the friction force.
  • There is a disagreement on the interpretation of the relationship between area and normal reaction, with some insisting that the original statement is misleading.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the relationship between friction, area, and normal reaction. Multiple competing views remain, with some participants defending the standard model while others highlight potential exceptions.

Contextual Notes

There are unresolved questions regarding the definitions and conditions under which friction might depend on area, as well as the accuracy of the quoted statement from the book.

Amru123
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Friction is independent of area of surfaces in contact as long as the normal reaction remains the same.I agree that it does not depend and so says it's formula but the condition that it does when the normal reaction remains same looks odd to me..Can someone help me out to understand this?
 
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Amru123 said:
Friction is independent of area of surfaces in contact as long as the normal reaction remains the same.I agree that it does not depend and so says it's formula but the condition that it does when the normal reaction remains same looks odd to me..Can someone help me out to understand this?
What seems odd to you about it?
 
Chestermiller said:
What seems odd to you about it?
I can't see the connection between how the "remaining same of normal reaction" makes friction become dependent on "area"
 
Who says that the friction force depends on the area?
 
Chestermiller said:
Who says that the friction force depends on the area?
Oh my god! You are misunderstanding my question.I was reading a book at a neighbourhood library when I came across this statement "Force is independent of area of surface of contact except when the normal reaction remains the same" Which clearly means normal reaction makes force become dependent.Do you get what I mean? If you don't believe in the statement I mentioned,Kindly look it up.It's true but I can't understand how it could be.Do help me gain some knowledge about it if you get to know it.Thanks in advance
 
Amru123 said:
was reading a book at a neighbourhood library when I came across this statement "Force is independent of area of surface of contact except when the normal reaction remains the same"
Are you sure that's what you read? That's a puzzling statement.

In the 'standard model' of friction (where F = μN), the friction force does not depend on surface area of contact. Period. It does depend on the normal force pressing the surfaces together.
 
Amru123 said:
Oh my god! You are misunderstanding my question.I was reading a book at a neighbourhood library when I came across this statement "Force is independent of area of surface of contact except when the normal reaction remains the same" Which clearly means normal reaction makes force become dependent.Do you get what I mean?
No. Is this the exact quote? Maybe there is an example problem associated with this?
 
Amru123 said:
Oh my god! You are misunderstanding my question.I was reading a book at a neighbourhood library when I came across this statement "Force is independent of area of surface of contact except when the normal reaction remains the same" Which clearly means normal reaction makes force become dependent.Do you get what I mean? If you don't believe in the statement I mentioned,Kindly look it up.It's true but I can't understand how it could be.Do help me gain some knowledge about it if you get to know it.Thanks in advance

frustrating, isn't it?
 
Amru123 said:
Friction is independent of area of surfaces in contact as long as the normal reaction remains the same.

Not a very clear piece of technical explanation but essentially correct .

There are situations where the area of surfaces in contact determines the normal reaction . An example of this would be a simple sliding rectangular slab of constant thickness . The bigger the sliding contact area becomes the heavier the slab becomes and the bigger the normal reaction becomes .
 
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  • #10
Amru123 said:
Friction is independent of area of surfaces in contact as long as the normal reaction remains the same.

Amru123 said:
Force is independent of area of surface of contact except when the normal reaction remains the same

Which is it?
 
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  • #11
A.T. said:
Which is it?
It's the former."as long as".Except is not right.Just now referred a website.Kindly bare my blunder.
 

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