Source: https://guthlabs.ai/docs/instruments/1d-elastic-collision-solver/implementation/

instrument implementation / implementation-contract

# 1D Elastic Collision Solver implementation

A source-bound implementation contract for 1D Elastic Collision Solver; 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**: t4-203

**Effect**: Computation or source lookup only

## Input and validation requirements

The formulas produce undefined results when m1+m2=0, and the specification gives no stated input validation for zero or negative masses. The solver also has no explicit collision-applicability branch for receding inputs and no stated sign convention.

## 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": 2,
    "m2": 3,
    "v1": 5,
    "v2": -1
  },
  "expected_outputs": {
    "v1_prime": -2.2,
    "v2_prime": 3.8,
    "KE_initial": 26.5,
    "KE_final": 26.5,
    "KE_conserved": true
  },
  "working": "m1+m2=2+3=5. v1'=((2-3)*5+2*3*(-1))/5=(-5-6)/5=-11/5=-2.2. v2'=((3-2)*(-1)+2*2*5)/5=(-1+20)/5=19/5=3.8. KE_initial=0.5*2*5^2+0.5*3*(-1)^2=25+1.5=26.5 J. KE_final=0.5*2*(-2.2)^2+0.5*3*(3.8)^2=4.84+21.66=26.5 J."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/1d-elastic-collision-solver/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/1d-elastic-collision-solver/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/1d-elastic-collision-solver/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`