1 / 8

Forces Related to Friction

Forces Related to Friction. F f = µ • F n µ = F f / F n µ is the coefficient of friction. F a = Applied force. F f = force of friction. F n. F g =Weight. dragging a box across the floor. Friction is a force. Opposes motion

robbin
Télécharger la présentation

Forces Related to Friction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Forces Related to Friction Ff = µ • Fn µ= Ff / Fn µ is the coefficient of friction Fa = Applied force Ff =force of friction Fn Fg =Weight dragging a box across the floor

  2. Friction is a force • Opposes motion • depends on the smoothness of the object and the surface it is moving on • depends on the weight of the object • Force of friction = µ x normal force • µ is coefficient of friction • related to smoothness • 0.1 for ice, 0.2 for smooth, 0.5 for rough surface

  3. Measuring force of friction • When block moves at constant velocity, the force of friction equals the applied force • The force of friction opposes the applied force • If the surface is flat, the normal force equals the weight. • The force of static friction is usually slightly larger than the force of sliding friction.

  4. Static and Kinetic Friction • Static Friction force happens when surfaces do not slip past each other • walking on the floor • pushing on a book before it moves • Kinetic friction happens when surfaces slide • sliding in stockings on waxed floor • pushing a book moving on the desk • Force of static friction keeps increasing until the object moves • Force of static friction is greater than Force of kinetic friction • Static and Kinetic friction obey the same laws • static is greater than kinetic

  5. Static and Kinetic Friction • Kinetic Friction • Object is moving • Surfaces are sliding passed each other • Static Friction • Objects not moving • Static Friction balances force of the push

  6. Static and Kinetic FrictionABS Brakes

  7. Unbelievable Friction Facts • Force of friction does not depend on area • thin block and wide block have same Ff • Force of friction increases with weight • Coefficient of friction is independent of weight •  does not depend on weight •  does not depend on area •  depends only on the two surfaces

  8. Ramp at an angle • The normal force is less than the weight • A part of the weight opposes the frictional force (down ramp) • As the angle gets larger, normal force decreases and part of weight down ramp increases.

More Related