Friction

Mechanics · 1699

Equation: F_f ≤ μ_s N (static), F_f = μ_k N (sliding)
Field: Mechanics
Named After: Guillaume Amontons
Year: 1699

Symbols

F_f the friction force · N the normal force pressing the surfaces together · μ_s, μ_k the coefficients of static and kinetic friction, properties of the pair of surfaces

Significance

Friction is proportional to the load and independent of the contact area — Amontons's laws of 1699, which da Vinci had in his notebooks two centuries earlier and Coulomb refined in 1785. Static friction is what a knot, a masonry anchor and a clutch rely on; kinetic friction is what a brake pad and a bearing pay. The coefficients are empirical, and the honest tables give ranges.

Skills

Rigging a Load with Pulleys Essential Knots Anchoring into Masonry Sharpening an Edge Follow, Draw and Stun Using Side

Required By

Throw Slide to Roll Rolling Resistance Cushion Rebound

Referenced by

equation

Cushion Rebound Rolling Resistance Slide to Roll Throw

skill

Anchoring into Masonry Essential Knots Follow, Draw and Stun Rigging a Load with Pulleys Sharpening an Edge Using Side

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