1. The Coefficient of Static Friction Renate Fiora

2. Experiments show a direct relationship between the force of static friction and the normal force. In other words, as the normal force is increased, the force of friction measured also increases. So the force of friction is directly proportional to the normal force. This means that the friction is the same as the normal force after it’s been multiplied by some constant number. We call this constant the coefficient of static friction. – It represents the maximum force of friction, after which the object starts moving. – It’s written as  s, pronounced “mu”.  F f  F N  F f = k F N  F f =  s F N mass friction

3. So,  s varies with the type of surface? Sure, smoother surfaces are more slippery. Just think about sliding across these surfaces: – A shag carpet – A freshly waxed hardwood floor – An ice rink The more slippery the surface, the less the coefficient of static friction is for it.