Static & kinetic friction
Static friction f ≤ μsN is passive; once F exceeds μsN the block slides with kinetic friction f = μkN.
Newton’s laws (senior)Hooke, friction, force composition, apparent weight.
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Static & kinetic friction
Static friction is passive (f ≤ μsN); once F exceeds the threshold μsN, friction drops to kinetic f = μkN and the block accelerates.
Static friction is passive (f ≤ μsN); beyond threshold it becomes kinetic f = μkN.
Key formulas
f_s\le\mu_s Nf_k=\mu_k NF>\mu_s N\Rightarrow a=\frac{F-\mu_k mg}{m}
How to use
- Set applied force F, mass m, μs and μk.
- Increase F to find the static-to-kinetic transition.
- Compare readouts to understand the two friction regimes.
Applications
- Static & kinetic friction: Static friction is passive (f ≤ μsN); beyond threshold it becomes kinetic f = μkN.
- Classroom focus: once F exceeds μsN the block slides with kinetic friction f = μkN.
FAQ
Why are static and kinetic friction different?
Static friction auto-balances the applied force up to μsN; once sliding, friction drops to μkN (typically μk < μs).
What does MVP mean on this page?
An interactive sketch with formulas and parameters. Polished Ready labs are the full bench experience.
What does the “Static & kinetic friction” lab practice?
Tune parameters and match readouts to the “Static & kinetic friction” relations — useful for prep and demos.
Is force always along velocity?
No. Net force aligns with acceleration; velocity can point elsewhere.