Question

Can someone please explain friction. i don't even understand the concepts parts!
bobpursley
Friction is a way work is converted to heat. The force of friction is proportional to the normal force on the mass, and proportional to some number (coefficent of friction).

Friction cannot do work, but it can absorb work.

http://www.youtube.com/watch?v=a5SOCxYft20&NR=1