1. FRICTION
•Definition of Friction
•Types of Friction
•Limiting Friction force
•Normal Reaction
•Co – Efficient of friction
•Angle of friction
•Laws of static friction
•Laws of Dynamic friction
2. Definition of Friction
"The opposing force, which acts in the
opposite direction of the movement of the
upper Body ,is called "FRICTION
FORCE", or simply “ FRICTION ".
3. Types of Friction
• Generally we classify the friction in two
categories –
(1) Static friction
(2) Dynamic friction
Static friction
when the body is in rest condition then the
friction force exerted by the body is called "static
friction".
4. Dynamic friction
when the body is in moving condition then
the friction force exerted by the body is
called is called "Dynamic friction“.
Dynamic friction is also classified into three
categories.
(i) sliding friction
(ii) Rolling friction
(iii) Pivot friction
5. LIMITING FRICTION FORCE
The maximum value of the friction force at
which the body resting on the another body start
to slide. If Limiting friction force is “F” and
applied force is “P”, then
(i) If F > P (no motion between two bodies)
(ii) If F = P (no motion between bodies)
(iii) If F = P (motion will be there)
6. NORMAL REACTION/FORCE
It is the net force
compressing two
parallel surface together
and the direction of the
reaction force will be
perpendicular to the
surface on which its act.
7. COEFFICIENT OF FRICTION
"It is defined as the ratio of the ratio of the
limiting friction force to the normal reaction
force".
It is represented by the "μ".
it is given by -> μ = F / Fn (limiting
friction/normal reaction)
8. ANGLE OF FRICTION
"The minimum inclination of any plane to
the horizontal is such that the body resting
on the inclined plane tend to move down the
plane, then this minimum inclination of the
plane is known as ANGLE OF FRICTION".
9. LAWS OF STATIC FRICTION
The applied force will be
equal in magnitude with
friction force.
The ratio of the limiting
friction force to the normal
reaction force is called
coefficient of static friction.
The force of friction is
dependent on the roughness
of the surface but
independent on the area of
10. LAWS OF DYNAMIC FRICTION
The direction of the friction force will
be opposite to the direction of motion
of the body.
The ratio of the dynamic friction to
the normal reaction is a constant.
As we increase the speed f the
moving body then the friction force
decrease.
