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

instrument / verified-clean

# Newton's Law of Gravitation Calculator

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

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/newton-s-law-of-gravitation-calculator/qualification/>)

## 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**: t4-071

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The algebraic formula is correct, but the specification is incomplete because input units, the exact numerical value/version of G, the center-to-center meaning of r, and the valid spherical-body domain are not stated. The honest label should say that the instrument returns gravitational-force magnitude in newtons under SI-unit assumptions, not a force vector; 'n/a' is insufficiently informative.

### Formula and scope findings

- F=Gm1m2/r² is the standard magnitude formula for two point masses, or for appropriately separated spherically symmetric bodies, but the specification does not constrain spherical bodies to cases where this simplification is valid; it is not generally valid for arbitrary overlapping finite spheres.

- The output is only force magnitude. A direction or vector is not computed, so the instrument should not label the result as a complete force vector.

### Unit assumptions

- m1 and m2 must be masses in kilograms (kg).

- r must be center-to-center separation in meters (m), not surface-to-surface separation.

- F is returned in newtons (N).

- Use G=6.67430×10^-11 N·m²/kg², explicitly identifying the CODATA release or numerical constant used.

- Inputs should satisfy m1≥0, m2≥0, and r>0; ordinary physical masses are strictly positive.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

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.

## 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": {
    "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."
}
````

## 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`