Ce diaporama a bien été signalé.
Le téléchargement de votre SlideShare est en cours. ×

# frictiion-ppt.pptx

Publicité
Publicité
Publicité
Publicité
Publicité
Publicité
Publicité
Publicité
Publicité
Publicité
Publicité
Prochain SlideShare
friction ppt
Chargement dans…3
×

## Consultez-les par la suite

1 sur 31 Publicité

# frictiion-ppt.pptx

engineering and 12th

engineering and 12th

Publicité
Publicité

## Plus De Contenu Connexe

Publicité

### frictiion-ppt.pptx

1. 1. Types of Friction
2. 2. What is Friction?  Friction is the resistance to the sliding, rolling, or flowing motion of an object due to its contact with another object.  When a moving object comes in contact with another object, friction is the opposing force that slows or stops the moving object.
3. 3.  Without friction, an object would continue to move at constant speed forever.  The strength of the force of friction depends on the type of surfaces and how hard the surfaces push together.  Rough surfaces produce greater friction than smooth surfaces.
4. 4.  Without friction you could not  Write  Drive a car  Fly an airplane  Why not?
5. 5. Four Types of Friction  Rolling Friction  Static  Sliding Friction  Fluid Friction
6. 6. What do all these things have in common?
7. 7. Rolling Friction  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. 8. What do all these things have in common?
9. 9. Static Friction  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.
10. 10. What do all these objects have in common?
11. 11. Sliding Friction  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
12. 12. What do all these things have in common?
13. 13. Fluid Friction  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.
14. 14. Ways to Reduce Friction  Smooth the surface  Replace rolling with sliding  Add oil or another type of lubricant
15. 15. Friction Song  What is friction?  Friction Video
16. 16. Gravity and Free Fall  An object is in free fall when the only force acting on the object is gravity.  Free-falling objects do not encounter air resistance.  In free fall, the force of gravity is an unbalanced force.
17. 17. Calculating Free Fall All objects in free fall accelerate at the same rate – 9.8 m/s² - regardless of their mass. in one second = 9.8 m/s² in two seconds = 19.6 m/s² in three seconds = 29.4 m/s² in four seconds = ________ The velocity continues to increase as the object falls.
18. 18. Gravity, Free Fall, and Projectile Motion  An object that is thrown is called a projectile.  If there is no air resistance, an object that is dropped and an object that is thrown are both in free fall.  Without the force of air resistance, both objects will hit the ground at the same time.
19. 19. Gravity and Air Resistance  Most objects falling through air experience a type of fluid friction called air resistance.  Air resistance is not the same for all objects.  The greater the surface area of the object the greater the air resistance.  However, since the elephant has more mass, it has more downward force of gravity and falls faster.
20. 20. What type of friction?
21. 21.  Static Friction
22. 22. What type of friction?
23. 23.  Rolling Friction
24. 24. What type of friction?
25. 25.  Fluid Friction
26. 26. What type of friction?
27. 27.  Static Friction
28. 28. What type of friction?
29. 29.  Sliding Friction
30. 30. What type of friction?
31. 31.  Fluid Friction