Maximum Static Friction Calculator
Enter the static friction coefficient and normal force to compute the maximum static friction f_s,max = μ_s·N.
Input Data
Results
At a glance:Static friction is the contact force that opposes the initiation of sliding between two surfaces. Its magnitude can vary from zero up to a maximum f_s,max = μ_s·N, where μ_s is the coefficient of static friction (a property of the two surfaces) and N is the normal force. If the applied force is below this limit the object stays at rest; at the limit it is on the verge of moving. Once sliding begins, kinetic friction (usually smaller than μ_s·N) takes over.
Formula
Maximum static friction: f_s,max = μ_s·N
How to Use
- Enter the static friction coefficient μ_s.
- Enter the normal force N (N).
- The calculator returns the maximum static friction f_s,max.
Case Studies
Pushing a crate
μ_s = 0.5, N = 196.2 N (20 kg on Earth).
f_s,max = 0.5 × 196.2 = 98.1 N.
A push above 98.1 N will start the crate sliding.
FAQ
Why is static friction usually larger than kinetic friction?
Surfaces settle into microscopic contact when at rest, increasing adhesion; once sliding, contact points break and reform continuously, giving a slightly lower average resistance. Hence μ_s ≥ μ_k.
Does static friction depend on contact area?
For most everyday dry surfaces, the maximum static friction is approximately independent of apparent contact area and depends mainly on μ_s and N.
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References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.