Source: https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/implementation/

instrument implementation / implementation-contract

# Newton's Law of Gravitation Calculator implementation

A source-bound implementation contract for Newton's Law of Gravitation Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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**: t4-071

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification omits input units, allowing a plausible centimetre-versus-metre interpretation that changes the result by a factor of 10000. The calculator must also reject r = 0 rather than return a numeric result. No actual formula branch exists to switch.

## 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": {
    "m1": 5,
    "m2": 10,
    "r": 2,
    "mass_unit": "kg",
    "distance_unit": "m"
  },
  "expected_outputs": {
    "F_N": 8.342875e-10
  },
  "working": "F=Gm1m2/r²=(6.67430×10^-11)(5)(10)/(2²)=(6.67430×10^-11)(50)/4=(6.67430×10^-11)(12.5)=8.342875×10^-10 N."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/qualification/>)

## 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`