How is friction force related to surface area?

1 Answer
May 30, 2015

Force of friction is independent of the area of contact.
The force depends on the normal reaction force and the nature of the surfaces in contact. If #N# is the normal force and #mu""_f# be the coefficient of friction then, the force of friction is given as :

#F = mu""_f*N#

These laws are approximate.
When dealing with static friction however, don't apply the equation directly without knowing that maximum amount of static friction is coming into play.