Next: Problem Solving Strategy
Up: Friction
Previous: Friction
 1.

f_{s}N where is the coefficient of static
friction and
N is the magnitude of the normal force. Equality holds when
the object is on the point of slipping:
f_{s(max)} = N .
 2.

f_{k} = N where is the coefficient of kinetic
friction and
is approximately constant for any given pair of materials.
 3.
 Values of and depend on the nature of the surfaces that
are in contact. Usually
< . Examples: rubber on concrete
= 1.0, = 0.8 ; waxed wood on wet snow
= 0.14, = 0.10.
 4.
 The direction of the force of friction is opposite to the direction the
object wants to move.
 5.
 and are nearly independent of the area of contact between
the two surfaces.
 6.
 is nearly independent of the velocity of the object under
consideration.
wwwadmin@theory.uwinnipeg.ca
10/9/1997