3. When applied force = 0
Fa = 0 A =-fk/ m No motion occurs, the body stops
Relation between Coefficient of Static & Kinetic friction
fk = μk N
fs =< μs N
fs > fk( to keep the body moving)
μs N > μk N Or, μk < μs Coefficient of kinetic friction is smaller than the coefficient of static friction.
Rolling friction o
o
o
Rolling friction is applicable for bodies whose point of contact keeps changing
It is the force that opposes the motion of a body which is rolling over the surface of another
Bowling balls, rotating wheels are examples illustrating Rolling friction