Friction Friction results from relative motion between objects. Frictional forces are forces that resist or oppose motion.
Coefficient of friction ( ) —Feet on rocks = large —Polar bear on ice = small
Friction (A Fun Formula) F f = F n fun get it?
Friction (A Fun Formula) F f = F n Normal force (N) Coefficient of friction No units! Friction force (N)
Friction F f = F n = F f F n F n = F f / To solve for frictional force To solve for normal force To solve for coefficient of friction
Calculate force of friction A box weighs 100 N (F n ). As the box is pushed horizontally, the coefficient of sliding friction is Determine the force of friction resisting the motion.
To solve for frictional force: F f = F n F n = 100 N F f = (0.25)(100 N) F f = 25 N