Terminal Velocity Calculator 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-with-binding-errata

Evidence ID

t2-035

Effect

Computation or source lookup only

Input and validation requirements

The specification provides no stated validation behavior for zero or negative density, drag coefficient, or area, so the raw formula can produce division by zero or a non-real square root. It also returns only a speed magnitude, leaving the sign convention ambiguous. The formula has no true multi-regime branch, so a correct implementation must explicitly reject invalid-sign inputs rather than silently treating them as a second physical branch.

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": {
    "mass": 0.1,
    "mass_unit": "kg",
    "Cd": 0.47,
    "area": 0.01,
    "area_unit": "m^2",
    "air_density": 1.225,
    "air_density_unit": "kg/m^3"
  },
  "expected_outputs": {
    "terminal_velocity": 18.46,
    "terminal_velocity_unit": "m/s"
  },
  "working": "Use g = 9.81 m/s^2. Numerator = 2 × 0.1 × 9.81 = 1.962. Denominator = 1.225 × 0.47 × 0.01 = 0.0057575. Ratio = 1.962 / 0.0057575 = 340.7729. Square root = sqrt(340.7729) = 18.4600 m/s, so terminal velocity ≈ 18.46 m/s."
}

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-tranche2/tranche2-results.json