Slashdot Mirror

← Back to Stories (view on slashdot.org)

Why Physicists Don't Like To Talk About Friction

Posted by timothy on from the at-least-in-mixed-company dept.

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.

1 of 34 comments (clear)

  1. car tire area and slipping by raygundan · · Score: 4, Informative

    Wider car tires work better because the rubber is less likely to tear due to the force. When stopping or starting, the force on the car tires is often enough to tear off rubber (hence the tracks you leave on the road). This means that the limiting factor in tire traction is not the actual coefficient of friction, but rather the strength of the tire. (Because we are sliding due to tearing rubber *before* we run exceed our force of friction) Since the strength of stuff *is* dependent on area (think 2x4s vs. a broomstick), wider tires will not tear as quickly, meaning more of the friction is available before we slide.

    So it's not the friction that's changing due to area, but how quickly the tire tears.

    For a reference (quick search on google) see:
    http://www.cosm.sc.edu/~phys153/tirefriction.htm l