Friction Calculator

Estimate static or kinetic friction forces using μ and the normal force

Inputs

Friction force: F = μ · N, where N is the normal force. Static μ gives the maximum before motion; kinetic μ applies during motion.

Helps estimate effective weight components (N = mg·cosθ if you already computed mg).

How to Use the Result

  • The static friction value is the threshold; any applied force greater than this causes motion.
  • Kinetic friction is typically lower than static friction for the same surfaces.
  • If you only know mass m, compute N = m · g · cosθ first, then plug it into the calculator.

How friction force is calculated

Formula

Fᶠ = μN

The coefficient of friction multiplies the normal force. Static and kinetic friction use different coefficients.

Worked example

With μ = 0.30 and N = 100 N, the friction-force magnitude is 30 N.

Common mistake

The normal force is not always equal to weight, especially on slopes or with other vertical forces.