Source: https://guthlabs.ai/docs/instruments/0-60-mph-estimator-educational/
instrument / verified-clean
# 0-60 mph Estimator (Educational)
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**: Everyday & Life
**Tranche**: tranche-4
**Evidence ID**: t4-151
**Ledger rows**: 1
No ledger note is attached.
## Review findings
The base arithmetic is correct only conditionally: time_s = k × sqrt(weight_lb / hp). Final approval requires the exact published calibration constant and citation, the calibration range and error metrics, and an explicit drivetrain adjustment formula. The supplied k = 1.25 and neutral factor = 1.0 in the vectors are illustrative test parameters, not validated production values.
### Formula and scope findings
- The stated formula is a plausible empirical correlation, but there is no universal standard value for k; the calibration constant, reference dataset, fitted domain, and source citation are missing.
- The input includes drivetrain type and promises an adjustment factor, but the formula does not define any drivetrain adjustment factor or how it modifies time_s.
- The formula is only conditionally valid within the calibration range; extrapolation to unusual vehicle weights or horsepower values is not justified.
- The formula assumes horsepower is a comparable power rating across vehicles and does not specify whether engine, crank, or wheel horsepower is required.
### Unit assumptions
- weight_lb must be vehicle weight expressed in avoirdupois pounds, not kilograms or mass in another unit.
- hp must be horsepower using the same horsepower definition as the calibration dataset; engine/crank horsepower and wheel horsepower are not interchangeable.
- k has units of seconds divided by the square root of lb/hp, so its numeric value is valid only with weight in pounds and power in horsepower.
- The test vectors use an illustrative k = 1.25 and a neutral drivetrain adjustment factor of 1.0 solely to demonstrate the arithmetic; the spec must provide and cite the actual calibrated value.
- The output time_s is in seconds.
## Boundary hardening
**BREAK_CLAIMED** · SELF_FLAGGED
The specification does not provide the empirical calibration constant k or any drivetrain adjustment factors, so ordinary valid inputs cannot produce a numeric estimate. It also does not state input validation behavior for zero or nonpositive horsepower, zero weight, or unit ambiguity; zero horsepower causes division by zero and must be rejected.
## 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": {
"weight_lb": 3000,
"horsepower": 200,
"drivetrain_type": "neutral_example",
"drivetrain_adjustment_factor": 1,
"k": 1.25
},
"expected_outputs": {
"time_s": 4.841229
},
"working": "weight_lb / hp = 3000 / 200 = 15. sqrt(15) = 3.872983. drivetrain adjustment = 1.0, so 3.872983 × 1.0 = 3.872983. time_s = 1.25 × 3.872983 = 4.841229 s."
}
````
## 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`