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/sci/ - Science & Math

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6315374 No.6315374 [Reply] [Original]

Why doesn't the area of contacting surfaces affect on friction?

Serious question

>> No.6315386

because friction is converting horizontal force to vertical and you're not heavier if you stand on one foot

>> No.6315383

It does?
The more area of contact the more friction, for example if you take two books and cross their pages you won't be able to pull them apart due to friction.

>> No.6315388

i like your pic , OP

>> No.6315410

>>6315374

it does!

each atom/molecule in contact with each other contributes to the total force experienced. just with a smaller area less molecules are in contact, but with a larger pressure so it cancels out.

>>6315386
this guy is full of shit

>> No.6315412

>>6315388
course you do you autismlord

>> No.6315426

>>6315410
Then why is:
>Amontons' Second Law: The force of friction is independent of the apparent area of contact.

>> No.6315429

>>6315426
Also I'm actually talking about coefficient of friction, but this applies to it too?

>> No.6315440

>>6315426
> just with a smaller area less molecules are in contact, but with a larger pressure so it cancels out.

If you have a large area, then many molecules are pushing against each other, creating friction. If you have a small area, then there are fewer molecules in contact, but they have more pressure from the weight of the object. It all evens out.

>> No.6317101

>>6315426
http://depts.washington.edu/nanolab/ChemE554/Summaries%20ChemE%20554/Introduction%20Tribology.htm

paragraph 3.

you're facing terminology problem you all (I guess)

>> No.6317113

>>6315374
if your normal force is F= S*P, where S is the surface of contact, and P an average pressure, then for a different surface, you see that it's P that changes.

>> No.6317125

>>6315374

Friction is a force that is proportionate to the weight of the object. F(friction) = u(coefficient of friction) * N (normal component of reaction of the surface). Generally N = -G

And since G is a volumetric force it isn't dependent of the surface size.

>> No.6317133

>>6315410

>this guy is full of shit

He is not, he is correct. Go read a basic book on dynamic.

>> No.6317137

>>6317133

Edit:

He missplaced horizontal and vertical. It should go

>because friction is converting vertical force to horizontal and you're not heavier if you stand on one foot

>> No.6317160
File: 27 KB, 1257x675, friction.png [View same] [iqdb] [saucenao] [google]
6317160

Here is the visual

exlpanation:

Since G is a volume force, it doesn't depend on the surface of the object, just it's volume and mass, therefore F doesn't depend on the surface.

>> No.6317213

a specific areas friction is directly proportional the the force holding the areas together if you double the area, then the friction doubles, but if its the same object then the force on each area halves, so it balances out.