Friction
Friction is a force that resists the movement of two contacting surfaces sliding relative to each other. Frictional forces act tangential to the surface at the point of contact and act in opposition to the possible or existing motion between the surfaces.
Limit on friction force magnitude.
Variables \( F \) and \( N \) are the magnitude of the friction for \( \vec{F} \) and the normal force \( \vec{N} \), and \( \mu \) is the coefficient of friction.
Static Friction
Examples of coefficients of static friction:| System | Static friction \(\mu_s\) |
|---|---|
| Rubber on dry concrete | 1.0 |
| Wood on wood | 0.5 |
| Steel on steel | 0.6 |
| Shoes on wood | 0.9 |
| Shoes on ice | 0.1 |
Tipping vs. Slipping
tipping vs. slipping
To solve for X (the location of the normal force), one can write the equations of equilibrium.
Note: See below for an explanation of why the normal force does not act at the center of mass of the box.
Note explanation