Kinetic friction o
o o
Force that resists motion of one body over another with which it is in contact .
Denoted by fk As motion starts , fs vanishes and fk appears o
o fk ∝ N
Kinetic friction is Independent of the area of contact and velocity of the body
It varies with Normal reaction , N
fk = constant * N
fk = μk N ; μk is the coefficient of kinetic friction Three scenarios can arise in a body ’ s motion
1 . When applied force > fk
Fa > fk
( Fa – fk ) = ma a = ( Fa – fk )/ m
2 . When applied force = fk
Fa = fk
Therefore , a = 0 i . e . the body moves with uniform velocity