here in this presentation i explain the types of friction and their examples. and i explain world without friction is like this in video.

1. Group member Name:-
1) Ram bhavesh (150210119085)
2) Vaja akhil (150210119121)
3) Vala vivek (150210119123)
Subject:-
mechanics of solids
Topic:-
friction

2. • Friction is a force between two surfaces
that are sliding, or trying to slide across one
another, for example when you try to push a
toy car along the floor.
• Friction always works in the direction
opposite from the direction the object is
moving, or trying to move. It always slows
a moving object down.
Moving
Friction

3. Normal
Force FN
Friction
Force ff
Applied
Force F
Gravity
Force Fg
Fg = mg
FN = Fg
ff = F

4. Angle of repose
When granular material is heaped, there exists a limit
for the inclination of the surface. Beyond that angle, the
grains start rolling down. This limiting angle upto which
the grains repose (sleep) is called the angle of repose of
the granular material.
Significance of Angle of repose:
The angle that an inclined plane makes
with the horizontal, when the body supported
on the plane is on the verge of motion due to
its self -weight is equal to the angle of repose.
Angle of repose is numerically equal to
Angle of limiting friction

5.  Rolling Friction
 Static friction
 Kinetic friction
 Sliding Friction
 Fluid Friction

6.  Rolling friction is friction
that occurs between surfaces
in motion in which one of the
surfaces is a wheel, roller, or
ball.
 Examples:
 Riding a bike – tires and
ground
 Bowling – ball and lane

8.  Static friction is friction that
occurs when the surfaces in
contact are at rest (not in
motion).
 Examples:
 A book resting on a desk.
 A potted plant sitting on a
sidewalk.

9. frictionstaticoftcoefficien
Ff
s
sNs




FN
fs
F
Fg
The Force of Static
Friction keeps a
stationary object at
rest!

11. frictionkineticoftcoefficien
Ff
k
kNk




FN
fk
F
Fg
Once the Force of Static
Friction is overcome, the
Force of Kinetic Friction
is what slows down a
moving object!
Motion

13.  Sliding friction is
friction that occurs when
solid surfaces slide over
one another.
 Examples:
 Writing – pencil point
and paper
 Combing your hair –
surface of comb and
strands of hair

15.  The force that tries to slow objects down when they move
through a liquid or a gas. It's also known as "drag", or "air
resistance".
 All gases and liquids are fluids.
 An airplane and a swimmer both experience fluid
friction.

17. 1. The limiting frictional force f is directly proportional to
the normal reaction N exerted by the surface.
i.e. f ∝ N or f = N where  is a constant called
coefficient of limiting friction.
2. The kinetic frictional force f is directly proportional to
the normal reaction N exerted by the surface.
i.e. f’ ∝ N or f’ = ’N where  is a constant called
coefficient of kinetic friction.
Frictional force f
Applied
force FA
Normal
reaction N
For simplicity, take f = f’ = N and  = ’

18. 18
 If the surface is smooth,  = 0 ⇒ f = 0 N
 Coefficient of friction depends on the two
contacting materials.
For simplicity, take f = f’ = N and  = ’
Rubber Concrete (Dry)   0.6 – 0.85
Rubber Concrete (Wet)   0.45 – 0.75
 Frictional force does not depend on the area
of contact of the surfaces.