Friction Calculator
Calculate friction force from normal force and coefficient of friction. Covers flat surfaces, inclined planes, static vs kinetic friction, air drag, and power to overcome friction.
Friction Force (N)
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Type —
Extended More scenarios, charts & detailed breakdown ▾
Friction Force (N)
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Deceleration if only friction (m/s²) —
Professional Full parameters & maximum detail ▾
Static vs Kinetic
Max Static Friction Force (N) —
Kinetic Friction Force (N) —
Air Drag & Power
Air Drag Force (N) —
Power to Overcome Friction (W) —
Reference
Common Coefficients (reference) —
How to Use This Calculator
- Enter Normal Force (N) and Coefficient of Friction μ to find friction force.
- Use the Inclined Plane tab for mass on a slope — enter mass, angle, and μ.
- Use the Find Coefficient tab to calculate μ from measured forces.
- The Professional tab covers static vs kinetic comparison, air drag, and material reference table.
Formula
F_friction = μN | On slope: N = mg·cos(θ), F_f = μmg·cos(θ)
Air drag: F_d = ½ρv²C_dA | Power: P = F_friction × v
Example
N=100 N, μ=0.3 → F_friction = 30 N. Mass 10 kg on 30° slope, μ=0.3: F_f = 0.3×10×9.81×cos(30°) ≈ 25.5 N.
Frequently Asked Questions
- Friction force F = μN, where μ is the coefficient of friction and N is the normal force (perpendicular to the surface). Friction always opposes motion.
- Static friction prevents an object from starting to move (μₛ is typically higher). Kinetic friction acts on a moving object (μₖ is slightly lower). An object starts moving when applied force exceeds μₛN.
- Normal force N = mg·cos(θ). Gravity component along slope = mg·sin(θ). Friction force = μ·mg·cos(θ). Net acceleration = g(sin(θ) − μcos(θ)).
- Ice on ice: μ≈0.03. Lubricated steel: μ≈0.1. Wood on wood: μ≈0.4-0.5. Rubber on concrete: μ≈0.6-0.8. The coefficient is dimensionless.
- Drag force F_d = ½ρv²C_dA, where ρ is air density (1.225 kg/m³), v is speed, C_d is drag coefficient, and A is frontal area. Drag grows with the square of speed.