Quote:
Originally posted by rbayer
To clarify:
f=uN for simple surfaces. This does not involve area. However, for FIRST, area DOES matter. For example, try dragging a 1mm wide tire accross carpet and then try a 1m wide strip. Assuming both have the same mass, or at least the same net force acting into the carpet, the 1m wide will be harder to pull. My question is why.
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Humn. If my understanding is correct, the two strips will have the same resistance to sliding motion caused by friction, as long as the pair of surfaces involves the same materials, and the *normal force between the strip and the ground is the same*. The 1mm tire and 1m strip do not have similar normal forces with the carpet. If you did this by placing different width strips under the same weights and dragging the weight with only the strip in contact with the ground, the force of friction would be the same in the two cases.