Friction Independent of Area: Understand It Here

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Friction is generally independent of the contact area between surfaces, provided the normal force remains constant. A participant expressed confusion over a statement suggesting that friction could depend on area when the normal reaction is the same. The discussion clarified that while the standard model of friction (F = μN) supports the independence of friction from area, there are scenarios where the area can influence the normal force, thus affecting friction indirectly. Participants debated the wording of the original statement, highlighting the importance of precise language in understanding friction concepts. Overall, the consensus reinforced that friction does not depend on contact area under normal conditions.
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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 dependant 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 dependant.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 dependant.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 dependant.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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