This presentation is for quick recap for Friction . All important topics about Friction are covered . It is strictly based on Class 11 NCERT

1. FRICTION
Change means movement. Movement means
friction
~Saul Alinsky
~

2. Your Logo or Name Here
-Friction-
Whenever a body moves or tends to move over
the surface of another body, a force comes into
play which acts parallel to the surface of contact
and opposes the relative motion. This opposing
force is called friction. 1

3. Your Logo or Name Here
Types of Friction
Static Friction
Static friction acts on objects when they are
in a rest position. When both objects are a
rest or one object is little tilted then the
friction which resist the motion is known as
Static friction.
For Example: When you are hiking on a
mountain and each time you put your foot
on the trail the static friction develops
between your shoes and trail to maintain the
stability.
Fluid Friction
Fluid fiction is that fiction which acts upon
objects that are moving through fluids. This
type of friction develops in liquids, gases or
oils.
For Example: Whenever you tried to push
water through palm in a bucket or tub an
opposing force acts upon your hand, this
force is nothing but fluid friction.
Kinetic Friction
Kinetic friction is that friction which acts
upon two objects sliding on moving on each
other. It is exerted by one surface to
another when two surfaces rub against
each other. The magnitude of the force will
depend on the coefficient of kinetic friction
between the types of materials of the
matter
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4. Your Logo or Name Here
Types of Friction
Sliding Friction
Sliding friction is that friction which
acts on objects when they are sliding
over a surface. Sliding friction resists
the sliding motion of the objects, this
friction is weaker than the static
friction, therefore, we can easily slide
any object on the surface easily.
.
~ Rolling Frction
Rolling friction is that friction which
acts on the object when they are
rolling over a surface. This friction is
weaker than static and sliding friction.
This type of friction acts upon vehicles
because the wheels roll on the
surface.
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5. Your Logo or Name Here
Limiting Friction
maximum value of static friction that comes into play when the
body is just at the point of sliding over the surface of another
body
Law for Direction
Limiting friction acts tangential to
the surfaces in contact, in backward
direction (i.e., opposite to direction
of motion).
Law for magnitude
Limiting friction is directly
proportional to the normal
reaction acting on the body.
Law for dependence
Limiting friction depends
upon the nature (rough or
polished) and the material
(hard or soft) of the surfaces
in contact.
5

6. Your Logo or Name Here
Coefficient of Friction
The limiting friction is directly proportional to the normal
reaction. If F be the limiting friction and R be the normal
reaction, then
μ =F/R
F=μ R
Here μ is called coefficient of friction, μ does not has unit
and dimensions because it is the ratio, of two like
physical quantities.
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7. Your Logo or Name Here
Angle of Friction
It is the angle that the resultant
of limiting friction and normal
reaction makes with the normal
reaction. It is shown by θ in
diagram.
7

8. Your Logo or Name Here
Angle of Repose
It is the angle of inclination of a rough surface
with horizontal, such that a body kept over it, just
starts to sliding down
8
Figure 7.04 shows a body of mass m and weight mg kept on a
surface inclined at an angle θ with horizontal.

9. Thank You
Presented By
AVISHI TYAGI
:D
HAPPY LEARNING