Question:
Please explain the coefficient of friction. Thank You
Replies:
What level of explanation do you want? The coefficient of friction
is an empirical rule that is associated with the force required
to move one object rubbing against another relative to the force
with which the two objects are being pressed together. The rule
is that the required force for motion is linearly proportional to
the normal force, and the ratio between the two is the coefficient
of friction (always between 0 and 1). There are different coefficients
for different types of motion - there is a coefficient to get the
motion started, and another to keep it going, and yet another associated
with "rolling" as opposed to sliding.
Friction comes from the electrical interactions between the two
surfaces at the level of the atoms and molecules, and can often
be significantly reduced by interposing a liquid (a lubricant) between
the two surfaces, because then the upper surface slides on a layer
of lubricant which can move freely over the other layer of lubricant
attached to the lower surface.
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