Re: Friction

[Herb Schulz <herbs@interaccess.com>]

> Everyone seems anxious to teach that static friction is greater than sliding
> friction and demonstrate it with objects on ramps etc.  Yet, for most of us
> car tires are the most improtant application of friction we experience, and
> they work the other way around.  Anybody have any good demonstrations to show
> a case where static friction is less, to simulate tires?  Quite honestly, I
> think this is another case like the half a lens, and tides, where well
> intentioned teachers who are out of touch with the real world mislead  their
> students.  In this case wrong ideas about friction could lead to an accident.

Howdy again,

So, are you saying that a car stops faster if it's skidding than if the
tires are rolling (i.e., there is no RELATIVE motion between the point(s)
of contact of the tire and the surface: therefore STATIC friction)?  I
wonder why they made  anti-lock brakes?

Good Luck,

Herb Schulz
(herbs@interaccess.com)