Frictional forces.

scuddman

Where does the equation F (force of friction) = uN (Muu times normal force)
come from? How do you derive the u?

vincentchan

derive? it is a property of substance.... the easiest way is doing an experiment....

Crosson

It comes from a good sounding phrase:

"The force of friction is proportional to the normal force"

This is translated in to f = mN.

It isn't really worth anything to anyone, other then to show introductory students how complex phenomena can begin to be model. It is semi valid as a engineering rule, and good for teaching.