Friction is important in everyday life and in the operation of all devices with moving parts, but it is still very poorly understood. Since the time of Leonardo da Vinci we know the phenomenological laws that describe how static friction is usually proportional to the load force, and kinetic friction tends to be smaller than the static friction.
Friction is important in everyday life, but because it is everywhere we often take it completely for granted. Every time you stand still, walk, or hold an object, friction helps you to control movements. At the same time, the friction of moving parts in machines, and the associated wear, costs modern societies an enormous amount of energy and materials. Because friction is part of everything we do, human beings have been dealing with it since prehistoric times. We have phenomenological laws that describe how friction behaves, but they do not explain where it comes from. [caption id="attachment_2138" align="alignnone" … Continue Reading ››