SUVAT Kinematics Solver

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Physics

Tranche

calibration-1

Evidence ID

offline/source boundary

Ledger rows

1

No ledger note is attached.

Review findings

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.

Formula and scope findings

• 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.

Unit assumptions

• 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.

Boundary hardening

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.

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": {
    "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."
}

Related workflows

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-tranche2/batch10-output.jsonl
• BOUNDARY_HAZARD_CATALOG.json