Friction ppt by irtizah ahmad

1. Friction
Class 8th blue.
Science
by IRTIZAH

2. The force of Friction.
The force that opposes the relative motion
between two surfaces of objects when they
come in contact.

3. example of THE FORCE OF FRICTION.

4. factors effecting Friction.
• 1. On the nature of the two surfaces that are
in contact.
• 2. On the force that is acting on these
surfaces.

6. Types of friction.
• There are mainly four types of friction:
• 1.Static friction.
• 2. Sliding friction.
• 3.Rolling friction.
• 4. limiting friction.

7. Static friction
• Static friction is a force that keeps an object at
rest. Static friction definition can be written
as: The friction experienced when individuals
try to move a stationary object on a surface,
without actually triggering any relative motion
between the body and the surface on which it
is on.

8. Sliding friction
• We can define sliding
friction as the resistance
created by any two objects
when sliding against each
other.
Rolling friction
• Rolling friction, type of
friction that occurs when a
wheel, ball, or cylinder rolls
freely over a surface

9. Limiting friction
• Limiting friction is described as the friction
created when two static surfaces come into
contact with each other.

10. How is rolling friction caused?
• Rolling friction takes place when an object
rolls on the surface. Sliding friction takes place
when two surfaces are rubbed against each
other.
• Do you know friction is also caused in liquids?

11. Friction due to air.

12. Disadvantages of friction:
• Friction produces heat which damages the
moving parts of a machine.
• Friction produces wear and tear on the
contacting surfaces. This reduces the life of
machine parts, tyres and shoe soles.
• A lot of energy is wasted due to friction to
overcome it before moving.

13. Advantages of friction:
• Friction enables us to walk freely.
• It helps to support ladder against wall.
• It becomes possible to transfer one form of
energy to another.
• Objects can be piled up without slipping.
• Breaks of vehicles work due to friction.

14. Methods for Reducing friction:
• Make the surfaces little more smoother. ...
• Lubrication is another way to make a surface
smoother. ...
• Make the object more streamlined. ...
• Reduce the Normal force acting between the
surfaces in contact. ...
• Reduce the contact between the surfaces, so
that less number of bonds will be formed.

15. Methods of reducing friction