Friction Wedge / Inclined Plane Solver implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t4-166

Effect

Computation or source lookup only

Input and validation requirements

The generalized formula has a true singularity when cos(phi)-mu*sin(phi)=0, producing an undefined force that must be rejected rather than numerically evaluated. The unspecified sign convention for applied-force angle also changes the computed force from 61.4087 N to 87.1377 N for the same plausible angle input.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "W_N": 1000,
    "theta_deg": 30,
    "mu": 0.5,
    "phi_deg": 0,
    "branch": "impending motion up incline",
    "coefficient_type": "mu_s"
  },
  "expected_outputs": {
    "required_force_N": 933.013,
    "angle_of_repose_deg": 26.565051
  },
  "working": "θ=30°: sinθ=0.5, cosθ=0.8660254. φ=0°: cosφ=1, sinφ=0. Up-incline branch: F=W(sinθ+μcosθ)/(cosφ−μsinφ)=1000(0.5+0.5×0.8660254)/(1−0.5×0)=1000(0.9330127)=933.0127 N≈933.013 N. Angle of repose=atan(0.5)=26.565051°."
}

Other records

Sources and evidence

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

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json