Friction Force Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Physics — Kinematics/Projectiles/Orbits, Forces/Energy/Momentum, Rotational Dynamics, Gravitation, Oscillations/Waves, Optics, E&M Fields, Relativity, Quantum, Statistical Thermo

Tranche

tranche-4

Evidence ID

t4-250

Ledger rows

1

No ledger note is attached.

Review findings

The coefficient formulas are standard under the Coulomb-friction model, but the specification is incomplete for its claimed motion and friction outputs. Add applied/net tangential force, define actual static friction versus maximum static friction, and specify the mass-plus-angle configuration and angle units before release.

Formula and scope findings

• f_s,max=μsN is the standard maximum static-friction magnitude, not necessarily the actual static-friction force. When the object is stationary, actual static friction is min(|F_t|, μsN), where F_t is the net tangential driving force.
• f_k=μkN is the standard kinetic-friction magnitude only while the surfaces are sliding; it must not be reported as the friction force for a stationary object.
• The supplied inputs do not include an applied or net tangential force, so motion yes/no and actual static friction cannot be determined.
• If normal force is derived from mass and angle, the needed formula and physical configuration are unspecified. For a simple incline with no other forces, N=mg cos(θ), but other configurations produce different normal forces.

Unit assumptions

• μs and μk are dimensionless and nonnegative.
• N is a normal force measured in newtons; if mass is supplied, mass is in kilograms and g is in m/s².
• Angles are assumed to be in degrees in these test vectors; the implementation must explicitly define degrees versus radians.
• The motion tests assume F_t is the net tangential driving-force magnitude in newtons, with no other tangential-force ambiguity.
• Friction outputs are magnitudes; the friction direction is opposite the impending or actual motion.
• The illustrative μ table must not be treated as a material-certified measurement.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The extreme-magnitude vector causes μN = 10^616 to overflow to Infinity in ordinary JavaScript arithmetic. The calculator should reject or flag the nonfinite result instead of presenting it as a valid physical friction force.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "mu_s": 0.5,
    "mu_k": 0.3,
    "normal_force_N": 100,
    "tangential_force_N": 20
  },
  "expected_outputs": {
    "maximum_static_friction_N": 50,
    "kinetic_friction_if_sliding_N": 30,
    "actual_friction_N": 20,
    "motion": "no"
  },
  "working": "Maximum static friction = μsN = 0.5 × 100 = 50 N. Since |F_t| = 20 N ≤ 50 N, the object remains stationary. Actual static friction = 20 N. If it were sliding, kinetic friction would be μkN = 0.3 × 100 = 30 N."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json