What is the friction force or Friction?
The force , which is acting in opposite direction of
motion between the two contact surface is known as friction or friction force.
Note
1. Frictinal force is a non conservative force (depends
upon the path).
2. It is a contact force and always act parallel to the
surface.
What is limting friction.?
The maximum
value of frictional force is known as limiting friction. And the friction
maximum value of the force of which come into play before a body begins to
slide over the surface of another body is called limiting friction.
What is
co-efficient of Friction?
The co-efficient of friction is defined as the ratio
between frictional force (f) to the normal reaction (N) . It is denoted by μ
(mu) .
Characteristics
of co-efficient friction?.
1.The value of co-efficient of friction depends upon
the nature of surface (rough and smooth)
2.It has no
unit. It is just a number.
Types of friction
There are two types of friction :-
1.
Solid or dry friction (coulomb friction)
2.
Fluid friction
Dry friction : The friction acts between two un-
lubricates Or Dry surface , when there is tendency for relative motion.
How many types of solid or dry friction?.
It is two types
of solid or dry friction
Static friction
Dynamic or kinetic friction
Dynamic or
kinetic friction is two types.
Sliding friction
Rolling friction
Now Above is
terms is defined
Static Friction: If the applied force is less than
limiting friction, then there is no relative motion between them and the
friction act between the body and surface is known as static friction.
Dynamic or
kinetic friction: If the Applied force is more than limiting friction, then
these is a relative motion between them and the Friction act between the body
and surface is known as dynamic or kinetic friction.
Note.
Kinetic Friction is always less than the static
Friction.
Sliding
Friction: when a body is sliding over another body, then the friction between
body and surface is known as sliding friction.
Rolling Friction: When a circular body like wheel,
cylinder, sphere, roller, etc roll over the body and surface is known as
rolling friction.
Note. Rolling
Friction is always less than sliding friction.
Fluid Friction: when a lubricating fluid (like grease
or oil) is introduced between the contact surface of two bodies then the
friction between them is known as Fluid friction.