Find kinetic friction F = μ N from a friction coefficient and the normal force.
| Friction (N) | – |
Use this calculator for sliding (kinetic) friction: the opposing force is the coefficient times the force pressing the surfaces together. On a level floor the normal force is usually the weight mg. μ is dimensionless; rubber on dry concrete is often 0.6–0.8.
μ = 0.4 and N = 200 N give F = 80 N. This is the kinetic estimate, not the extra static peak before something starts to move, and not a temperature- or speed-dependent tyre model.
μ: Coefficient of kinetic friction, typically 0.1–1, zero or more.
Normal force (N): Force pressing the surfaces together, in newtons.
Friction (N): F = μ N.
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