Source: https://guthlabs.ai/docs/instruments/coulomb-s-law-calculator/implementation/

instrument implementation / implementation-contract

# Coulomb's Law Calculator implementation

A source-bound implementation contract for Coulomb's Law 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**: t5-168

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-separation input produces an undefined result and must be rejected. The specification also leaves unit conversion, signed-versus-magnitude force reporting, and the zero-force direction convention unspecified.

## 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": {
    "q1": 2,
    "q1_unit": "μC",
    "q2": 3,
    "q2_unit": "μC",
    "r": 0.5,
    "r_unit": "m"
  },
  "expected_outputs": {
    "F_N": 0.2157012430152,
    "direction": "repulsive"
  },
  "working": "q1=2×10^-6 C; q2=3×10^-6 C. q1q2=(2×10^-6)(3×10^-6)=6×10^-12 C². r²=(0.5)²=0.25 m². F=8.9875517923×10^9×(6×10^-12)/0.25=8.9875517923×10^9×2.4×10^-11=0.2157012430152 N. Both charges have the same sign, so the force is repulsive."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/coulomb-s-law-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/coulomb-s-law-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/coulomb-s-law-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-tranche5/tranche5-results.json`