A) \[{{\mu }_{s}}={{\mu }_{k}}\]
B) \[{{\mu }_{s}}>{{\mu }_{k}}\]
C) \[{{\mu }_{s}}<{{\mu }_{k}}\]
D) Cannot predict
Correct Answer: B
Solution :
If we increase the applied force, a stage comes, when the body is just at the verge of moving over the other. The static friction at this stage is obviously maximum. This maximum-value of static friction is called limiting friction. When we increase the applied force slightly beyond limiting friction, the actual motion starts. This does not mean that friction has disappeared. It only means that the applied force is now greater than the force of limiting friction.. The force of friction at this stage is called kinetic friction or dynamic friction. Kinetic friction is always slightly less than the limiting friction. This is because, once the motion starts actually, inertia of rest has overcome. Also, when motion has actually started, irregularities of one surface have little time to get locked again into the irregularities of the other surface.
You need to login to perform this action.
You will be redirected in
3 sec
