2007-10-26 08:41:51 · 5 answers · asked by xo_kayla_444 2 in Science & Mathematics ➔ Physics
Friction is mostly caused by contact forces between one surface and another. Those contact forces are mostly due to instantaneous bonding that occurs between the surfaces.
When a wheel ROLLS over the ground, no point touches the ground for very long. The time a patch of the wheel touches the ground is more or less instantaneous, so there is no time for those contact forces to arise.
There is some friction because the wheel will partially compress the surface, but that is in general less than the friction that would be seen in sliding objects.
Note, it is NOT based on surface area...otherwise a skidding object on wheels would have little friction as well.
2007-10-26 08:50:37 · answer #1 · answered by David Zukertort Rudel 3 · 0⤊ 0⤋
They dont reduce the friction, they change the friction from rolling friction to sliding friction, to static friction.
2007-10-26 15:49:52 · answer #2 · answered by Andy 3 · 0⤊ 1⤋
They don't... friction is how they work (if they didn't have friction, the wheel would sit and spin without moving the vehicle).
2007-10-26 15:48:09 · answer #3 · answered by Anonymous · 0⤊ 0⤋
because they roll instead of slide over the surface. At the points where there is sliding surface contact (the bearings) the coefficient of friction is small and the surface areas acted on are small.
2007-10-26 15:47:26 · answer #4 · answered by SteveA8 6 · 0⤊ 1⤋
It eliminates dragging friction, which is a big drag.
2007-10-26 18:56:02 · answer #5 · answered by Dr. R 7 · 0⤊ 0⤋