Source: https://guthlabs.ai/docs/instruments/suvat-kinematics-solver/mechanism/

instrument mechanism / verified-clean

# SUVAT Kinematics Solver mechanism

The inspectable method record for SUVAT Kinematics Solver, kept separate from implementation and qualification.

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

## Model scope

The honest-label statement correctly identifies an idealized constant-acceleration model and omission of drag, but it should also disclose signed 1D conventions, required coherent units, t>=0 behavior, inconsistent-input handling, and multiple-solution behavior. The listed equations themselves are standard and valid; the specification fails because one claimed standard equation is absent and the any-three-input promise is underspecified and not universally unique.

- The specification claims five standard constant-acceleration equations but lists only four. The commonly included fifth equation, s=vt-½at², is missing.

- The listed four formulas are correct for signed 1D quantities under constant acceleration, but the claim that any 3 of {u,v,a,t,s} always determine a unique solution is false. Some input combinations can produce no real solution or multiple solutions; for example, u=10 m/s, a=-2 m/s², s=20 m gives two positive times.

- Solving v²=u²+2as for v requires a sign choice; the equation alone determines only the magnitude of v, not its direction.

- The solver does not specify the required sign convention for velocity, displacement, and acceleration, nor whether elapsed time must be constrained to t>=0.

## Units and conventions

- All quantities must use a coherent unit system: u and v in units of length/time, a in length/time², t in time, and s in length.

- The formulas assume signed scalar quantities in one dimension; positive direction must be defined consistently.

- If mixed units such as km/h and m/s² are accepted, the implementation must convert them before arithmetic. The plain-arithmetic engine does not establish that such conversion occurs.

- Acceleration is constant over the interval, and t is normally a nonnegative elapsed time.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "u": 5,
    "a": 2,
    "t": 4,
    "units": "u in m/s; a in m/s^2; t in s"
  },
  "expected_outputs": {
    "v": 13,
    "s": 36,
    "units": "v in m/s; s in m"
  },
  "working": "v=u+at=5+(2)(4)=5+8=13 m/s. s=ut+½at²=(5)(4)+½(2)(4²)=20+1(16)=36 m."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The solver can encounter an undefined 0/0 computation and an underdetermined solution when a = 0 and u = v. It can also produce two valid nonnegative time branches for the same supplied u, a, and s, so a unique output is impossible without a branch-selection rule. Additionally, interpreting s as distance instead of signed displacement changes the result from 16 m to 34 m.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/suvat-kinematics-solver/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/suvat-kinematics-solver/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/suvat-kinematics-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-tranche2/batch10-output.jsonl`

- `BOUNDARY_HAZARD_CATALOG.json`