Question

what is friction? define static friction, limiting friction and kinetic friction

Answer 1

Friction
Friction is a force that opposes the relative motion between two surfaces of objects in contact. The force of friction always acts in a direction opposite to that of the applied force. Friction is due to irregularities on the surfaces of the objects in contact.
Static friction
The maximum fictional force present between any two objects when one object just tends to move or slip over the surface of the other object ,is called static friction.Static friction is a kind of starting fiction because an object just tends to start moving, it does not actually move.
Limiting friction
The maximum friction that can be generated between two static surfaces in contact with each other. Once a force applied to the two surfaces exceeds the limiting friction, motion will occur. For two dry surfaces, the limiting friction is a product of the normal reaction force and the coefficient of limiting friction.
Kinetic friction
Kinetic friction is a force that acts between moving surfaces. An object that is being moved over a surface will experience a force in the opposite direction as its movement. The magnitude of the force depends on the coefficient of kinetic friction between the two kinds of material.

Answer 2

$\huge{ \bold{FRICTION:-}}$

In our day to day life we use the word friction technically or practically.

▶Friction:- It is a force which oppose the motion or oppose the intension of motion.

❇ Friction is occurs at the point of contact.

❇ The direction of friction is common tangent.

❇ Friction is occur between the two surfaces.

❇ Friction adjust its value automatically and always oppose motion and intension of motion.



$\bold{ \underline{Static \: Friction :-}}$

❇When two objects having more relative motion between two bodies in contact is called Static friction.

❇Static friction doesn't exist by itself.

❇Static friction help us to start the motion or move.

❇For walking on ground or for starting a motion Static friction is necessary.



$\bold{ \underline{Limiting\: Friction:-}}$

❇ It is the maximum opposing force that comes into play, when one body is just at the verge of moving over the surface of the other body.

OR

It is the maximum value of static friction between surfaces of 2 object if applied force is increase beyond it to the object start, having realtive motion.

❇ To start a object or for starting a motion minimum limiting friction value must be applied.

❇The direction of force of limiting friction is always opposite to the direction in which body have intension to move.



$\bold{ \underline{Kinetic \: Friction:-}}$

❇ It is the opposing force that comes into play when one body is actually moving over the surface of another body.

In short:- If their is a realtive motion between bodies which is in contact is known as kinetic Friction.

❇ Kinetic Friction help us to stop the motion.

❇ Kinetic Friction is always slightly less than the limiting friction.

❇ Kinetic Friction is also known as dynamic friction.