Verified calculation capability

Specific force Calculation Capability

Rectangular M=Q²/(gA)+A ȳ with ȳ=y/2. Not hydraulic jump y2, not specific energy E, not Froude as the product, not Manning n, not Q=Av, not critical slope Sc. · Physics · Fluid

Capability ID physics.fluid.specific_force · version 1.0.0

Open calculator REST API MCP Evidence Evidence JSON Review policy

Model

Specific force

Specific force: M = Q²/(gA) + A y/2
Section: A = b y
Critical: Mc = (3/2) b yc²

Solve modes: force · depth

Inputs / Outputs

Canonical symbols for this capability. Agent schemas remain the contract.

Symbol	Quantity	Unit	Role
`b`	Rectangular surface width in m. Required. Alternatives: width, b_m, channel_width. Do not send side-weir B.	—	input / output
`Q`	Volume flow in m³/s. Required. Alternatives: flow, Q_m3_s.	—	input / output
`y`	Flow depth in m. Required for force. Alternatives: y_m, depth. Do not send y1, y2, yn, or yc.	—	input / output
`M`	Specific force in m². Required for depth. Alternatives: M_m2, specific_force, momentum. Do not send E.	—	input / output
`g`	Gravity in m/s². Optional; default 9.80665. Alternatives: g_m_s2.	—	input / output
`branch`	Depth invert branch: omit or subcritical (y>yc); super\|supercritical\|alternate (y<yc).	—	input
`y_alt`	—	—	output
`yc`	—	—	output
`Mc`	—	—	output
`ybar`	—	—	output
`A`	—	—	output
`v`	velocity	—	output
`Fr`	—	—	output
`model`	—	—	output

Assumptions / Validity

Declared scope for this capability. Do not use it outside this domain.

Assumptions

Rectangular specific force: M = Q²/(gA) + A ȳ with A=b y and ȳ=y/2; SI; default g=9.80665; M is m²
Unknown is M (force mode) or y (depth invert, subcritical y>yc by default); conjugate y_alt is reported; Fr is reported not an input
Not hydraulic jump y2 from Fr₁>1; not specific energy E=y+v²/(2g); not Froude as the product; not Manning n; not Q=Av; not critical slope Sc

Not supported

hydraulic jump y2 from Fr₁>1
specific energy E
Froude as the product
Manning n
Q=Av
critical slope Sc
trapezoid z

Example

One numerical check. The calculator page holds worked steps and FAQ.

Q=2 b=2 y=1 → M≈1.20394

Open this example in the calculator

Trust

Review-policy: engine tested — automated tests, sources, version lock, and evidence published. Supplemental to CVP; not Domain Expert Review. See CVP and Review policy.

Tier: Engine tested — catalog token engine_tested
Calculation version: 1.0.0
Evidence tests: 5/5 calculation tests · golden 0/0 · boundary 0/0 · property 5/5
Engine tested: Yes
Source checked: Yes
Supplemental domain review: Not performed
Named expert review: Not performed
Version lock: Supported (409 VERSION_MISMATCH)
Artifact consistency: Build verified · 1.0.0 (workspace artifacts agree)

Production attestation: Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-18T21:41:56.329Z
Semantic contract: PASS
Evidence attested at: 2026-09-18T21:41:55.460Z
Last production check: 2026-09-18T21:41:55.460Z
Public / cache: PASS
Origin: PASS

Call this capability

Human page, REST, and MCP share the same engine and calculation_version. Build verified hashes workspace artifacts only. After deploy, attest:production GETs canonical URLs twice — the public/cached view an Agent actually hits, and origin — including every /capabilities/{id} HTML page. Public Capability HTML version must match catalog before production attestation passes. Live Trust rows above fetch /.well-known/calculatorx-production-attestation.json and the output schema const. Build hashes: release integrity. That proves currently published page / engine / schema / evidence / MCP agree — not that a historical version is independently immutable. Production surface contract 1/1.

Tool id: specific-force
Engine: specific-force
REST: POST /api/v1/calc/specific-force
MCP: execute_calculation with capability_id: "physics.fluid.specific_force"
Agent input schema: Canonical (MCP / Agent)
Output schema: JSON Schema (latest)
Versioned input schema: Immutable pin (1.0.0)
Versioned output schema: Immutable pin (1.0.0)

References

Human-readable sources plus CVP reference evidence classes.

Sources

ISO 80000-4 — Mechanics — Volume flow rate and force
Chow, V.T. Open-Channel Hydraulics — Specific force and sequent depths

Try with an agent

Inspect this capability via same-origin MCP, then call execute_calculation.

curl -sS -X POST 'https://www.calculatorx.com/mcp' \
  -H 'Content-Type: application/json' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/call' \
  -H 'Mcp-Name: inspect_capability' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"inspect_capability","arguments":{"capability_id":"physics.fluid.specific_force"}}}'

Inspect the trust tier and required assurance level before execution. Pin calculation_version (1.0.0) when reproducibility matters. Full protocol notes: MCP docs.