It's perhaps the second week of your introductory physics course. Your instructor starts talking about friction and writes the following two formulas on the board. Then there is probably some sort of ...

Friction is responsible for about twenty percent of the world energy consumption. The main reason for this is that frictional forces slow down the motion of surfaces in contact: think of the moving ...

Introduction Sometimes friction can be annoying. It can make it difficult to push heavy things like furniture and it can even give you a nasty scrape if you fall. But friction is actually very ...