Source: https://guthlabs.ai/docs/instruments/gravitational-potential-energy-calculator/
instrument / verified-clean
# Gravitational Potential Energy 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]()[02**Mechanism**Method and assumptions]()[03**Implementation**Binding and validation]()[04**Qualification**Evidence and errata]()
## 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**: t4-095
**Ledger rows**: 1
No ledger note is attached.
## Review findings
NEEDS_REVIEW because the exact ambiguity is whether the local output is intended to be absolute U or ΔU, and because g, SI-unit requirements, the mode selector, and the reference level for h are unspecified. The honest label is currently n/a; the instrument should disclose the zero-at-infinity convention for the general formula and the reference level and g value for near-surface mode.
### Formula and scope findings
- U=−Gm1m2/r is correct for two point masses, or spherically symmetric bodies outside their mass distributions, with zero potential at infinite separation; r must be center-to-center distance.
- U=mgh is the near-surface change in potential energy (ΔU), not an absolute gravitational potential energy unless h is explicitly measured from a declared zero reference.
- The local formula requires a specified gravitational acceleration g; the spec lists masses and h but does not identify g as an input or declare a default value.
- The general and local calculation modes are not explicitly represented in the input contract, creating ambiguity about which formula and required fields apply.
### Unit assumptions
- Use SI units: kilograms for mass, meters for r and h, meters per second squared for g, joules for U.
- Use G=6.67430×10^-11 N·m²/kg² unless the instrument exposes G as an input or clearly documents this constant.
- For near-surface calculations, use g=9.80665 m/s² by default only if that default is explicitly documented; h is signed displacement from the chosen reference level.
- In the general formula, r is center-to-center separation and must be strictly positive.
## Boundary hardening
**BREAK_CLAIMED** · SELF_FLAGGED
The general formula has an undefined division-by-zero input at r=0 and must reject it rather than return a numeric result. A separate hazard is that general and near-surface outputs use different reference conventions, so switching modes can produce apparently inconsistent values unless the reference level is made explicit.
## 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": {
"mode": "general",
"m1_kg": 5.972e+24,
"m2_kg": 1000,
"r_m": 7000000,
"G_N_m2_per_kg2": 6.6743e-11
},
"expected_outputs": {
"U_J": -56941313714.2857
},
"working": "U=−Gm1m2/r\n=−(6.67430×10^-11)(5.972×10^24)(1000)/(7.000×10^6)\n=−(6.67430×5.972)×10^16/(7.000×10^6)\n=−39.8589196×10^16/(7.000×10^6)\n=−5.69413137142857×10^10 J\n=−56,941,313,714.2857 J"
}
````
## 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`