On 1/23/98 7:27 PM so and so Scott Gardner said. (And I quote)
>Since the list did so well on the water-displacement/painted cylinder
>questions, maybe you can help me out on one that my Dynamics profesor
>asked us about eight years ago. I still haven't found a definitive
>answer. It IS automobile-related, but not necessarily LBC.
> First, some background information: The coefficient of friction
>between to surfaces does not rely on the amount of surface area in
>contact, only on the weight of the object being moved. This is why a
>tall, skinny box is not any easier to slide across a floor if you
>have the small surface in contact with the box than if you have the
>big side in contact with the floor. This is true whether you're
>talking about sliding friction or static friction. (sliding friction
>is the box sliding across a floor, static friction is like a wheel
>rolling across the floor--no points on the floor and wheel ever
>actually slide relative to one another, but there's still friction,
>also known as rolling resistance).
> Here's his question. If the coefficient of friction is only
>dependent on the two surfaces in question and the weight of the
>object being moved, and not the amount of surface area in contact
>with the ground, why do drag racers use such wide tires? Discount
>anything having to do with cornering, since drag racers are just
>interested in straight-line movement. Those of you who still
>remember any dynamics classes you may have had can do the math
>yourself--On paper, a car should be able to generate the same
>forward force whether it is fitted with bicycle tires or 30" wide
>Mickey Thompson Slicks, as long as the rubber used in both tires is
>the same, and the weight of the car remains the same.
> I have an idea, but I don't want to prejudice the list.
>I'll post my hypothesis for confirmation or ridicule in a day or two.
>Scott
Moment of inertia?
Larry Macy
78 Midget
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