µ must be kidding!

* The Force of Friction depends on: * The surfaces in contact * The amount of the normal force * Whether the object is moving (kinetic) or stationary (static) * Ff = µFn

* µ = coefficient of friction which is a “unitless” number which depends on the surfaces in contact. * µ s = static coefficient of friction which is used when the objects are static (not moving relative to eachother. * µ k = kinetic coefficient of friction which is used when the objects are sliding relative to eachother.

* µ s > µ k Surfacesµ staticµ kinetic Wood on wood Rubber on concrete Banana peel on bugs bunny

* Ff = µ k F n * When objects are sliding this is always an equality * The kinetic coefficient of friction is less than the static coefficient of friction