(1) Static friction : The opposing force that comes into play when one body tends to move over the surface of another, but the actual motion has yet not started is called static friction.
(i) If applied force is P and the body remains at rest then static friction force F = P.
(iii) Static friction is a self-adjusting force because it changes itself in accordance with the applied force and is always equal to net external force.
(2) Limiting friction: If the applied force is increased, the force of static friction also increases. If the applied force exceeds a certain (maximum) value, the body starts moving. This maximum value of static friction upto which body does not move is called limiting friction.
(i) The magnitude of limiting friction between any two bodies in contact is directly proportional to the normal reaction between them.
FI ∝ R or FI =μsR
μs = F/R
Not depend upon