CE30-Lecture5 - Lecture 5 Friction What is Friction ?...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Lecture 5 Friction What is Friction ? Friction is ``a necessary evil of all motions. No matter which direction something moves in, friction pulls it the other way. Move something left, friction pulls right. Move something up, friction pulls down. It appears as if nature has given us friction to stop us from moving anything. Friction is actually a force that appears whenever two things rub against each other. Although two objects might look smooth, microscopically, they're very rough and jagged. As they slide against each other, their contact is anything BUT smooth. They both kind of grind and drag against each other. This is where friction comes from. But friction is not all bad. In fact, it has a lot to do with life as we know it here on Earth. Without it, we wouldn't be able to walk, sit in a chair, climb stairs, or use a mouse to surf the web. Everything would just keep slipping and falling all over the place. Speedy Speedo Swimsuit Introduction In preceding chapters, it was assumed that surfaces in contact were either frictionless (surfaces could move freely with respect to each other) or rough (tangential forces prevent relative motion between surfaces). Actually, no perfectly frictionless surface exists. For two surfaces in contact, tangential forces, called friction forces , will develop if one attempts to move one relative to the other. However, the friction forces are limited in magnitude and will not prevent motion if sufficiently large forces are applied. The distinction between frictionless and rough is, therefore, a matter of degree. There are two types of friction: dry or Coulomb friction and fluid friction . Fluid friction applies to lubricated mechanisms. The present discussion is limited to dry friction between nonlubricated surfaces. Charles-Augustin de Coulomb (1736-1806)...
View Full Document

This note was uploaded on 01/21/2012 for the course C 85 taught by Professor Papadopoulos during the Spring '08 term at University of California, Berkeley.

Page1 / 27

CE30-Lecture5 - Lecture 5 Friction What is Friction ?...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online