The Last Samurai

   

Kinetic Friction v.s. Static Friction

Kinetic friction occurs when two objects are moving relative to each other and rub together. The coefficient of kinetic friction is typically denoted as μ_k, and is usually less than the coefficient of static friction for the same materials.

Static friction is friction between two solid objects that are not moving relative to each other. Kinetic friction is when two objects are rubbing against each other. Putting a book flat on a desk and moving it around is an example of kinetic friction.