Was looking at the thread about vehicle dynamics (this one:
http://forums.pelicanparts.com/showthread.php?threadid=329482 ) and it got me thinking back to a discussion years ago with my high school physics teacher. We were discussing the implications of Coulomb equation with respect vehicle tires. For those who forget, the equation is this:
His position (and it makes sense, even if it's a bit simplistic) was that the size (width) of tires on a car had no bearing whatsoever on how "grippy" they would be, since the Ff (force due to friction) was a function of the coefficient of friction between the two surfaces (tire composition & pavement surface) and the "N" value ("normal force" - basically the weight of the vehicle). So a thin, skinny tire should in theory grip just as well on a drag strip as a wider, fatter one. His claim was that wide tires were largely a marketing ploy because they "looked cool", but actually did nothing to make the car grip better under acceleration and a powerful car would break the tires loose just as easily on a fat-tire-equipped rear end as a skinny-tire-equipped one.
Of course we all know this isn't entirely true in practice and there are other physical principles that must come into play here, but does anyone on here know exactly which ones they are and how these principles avoid conflicting with the Coulomb equation? Curious to know if anyone has thought about it. . .
The other implications of the formula make sense - heavier vehicles will "stick" better (and by Newton's Second Law, be slower to accelerate), tire composition determines frictional coefficent, which is very important (and can change with temperature, of course), etc. . . Just wondering about this one aspect where observed behavior seems to conflict with predicted behavior.