Friction

Friction

Friction is the contact force that opposes relative motion between surfaces. It is modelled as proportional to the normal force:

$f = \mu N$

• $\mu$ (mu) — coefficient of friction (dimensionless, depends on surface pair)
• $N$ — normal force in Newtons (perpendicular to surface)
• $f$ — friction force in Newtons

Static vs Kinetic

For a block on a horizontal surface: $N = mg$, so $f = \mu mg$.

Typical Coefficients

Your Task

Implement frictionForce(mu, N) returning the friction force magnitude in Newtons.