Re: friction

["Bernard G. Cleyet & Nancy Ann Seese" <georgeann@REDSHIFT.COM>]

I thought every frosh lab included this xpt., but then I "labbed" in the
Pleistocene.  We found it true (order of mag. change in area) for the
several surfaces we tested, within the measurement accuracy (admittedly
rather poor -- 5% ?  Would a 5% get one unstuck?)

I just thought of another horror: spinning wheels => heat => melted ice!

bc

Herbert H Gottlieb wrote:

> On Sat, 12 Feb 2000 16:37:24 -0800 Leigh Palmer <palmer@SFU.CA> writes:
>
> > Makes sense to me.
> >
> > I suppose you are worried about some textbook statement that the
> > force of friction is independent on the area of mutual contact. This
> > provides a good chance to point out that the model of friction given
> > is just that, a model, and in this case an iapplicable model.
> >
> > Leigh (from Deer Lake, which rarely freezes deep enough to drive on)
>
> If this model is inapplicable, please tell us why it does not
> apply in this case...
> On behalf of myself and all your other fans....
> ......   Thanks again Leigh..
>
> Herb Gottlieb asked....
>
> > > Suppose that your car is stuck on ice. thje wheels spin but the car
> > does not move. Your friend suggests that you let some air out of your
> > tires to increase the amount of friction.
> > > Does this make sense?