Why Physicists Don't Like To Talk About Friction

fm6 writes: "You would think that force required to overcome friction would be a function of the area of contact. But according to this Scientific American article, that's not true, and physicists don't have a really satisfying explanation." This is the sort of article that makes you want to go experiment with those teflon-coated disks made for moving furniture.

Comments

Hmm, is this harder than I am thinking

[labufadora]

It doesn't seem mysterious to me that it's related only to the force. The same force distributed over a wider area actually applies less force per square [your measure here]. So it's a wider area - big deal. It's compensated for by a proportionally smaller force per square area. Whatever atomic force is working at keeping the surfaces distinctly separated has to do less work at any single point when the force is acting in more places. The net effect? Surface area is irrelevant. Am I missing something? Is this explanation just way too simple? What's the catch?

Re:Hmm, is this harder than I am thinking

[kryzx]

The net effect? Surface area is irrelevant. Am I missing something? Is this explanation just way too simple? What's the catch?


The catch is that it's not true. The best example to disprove your hypothesis is car tires. If surface area were irrelevant it would not matter whether you had narrow or wide tires. A 1 inch wide tire and a 15 inch wide tire of the same material would acheive the same friction (and therefore acceleration/deceleration/turning power). This is obviously not true. There are definitely other factors involved, but I think it's clear that surface area has a significant effect.