Description
Return a signed planar moment under an axis-normal policy.
Mechanical inertia, torque and muscle-force projections require compatible axes, origins and geometric assumptions. A parallel-axis contribution, planar moment or ideal pennation factor is one local model term rather than a full anatomical load or muscle-activation calculation.
Return a signed planar moment under an axis-normal policy.
When to use this tool
Use Moment Arm Sign From Axis when evaluating the stated segment, moment, inertia or ideal muscle-geometry term.
How to use the tool and how it works
- Enter leverX, leverY, forceX, forceY, reverseNormal. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read signedMoment. Use the output convention below.
Return a signed planar moment under an axis-normal policy. signedMoment = (leverX*forceY-leverY*forceX)*(reverseNormal ? -1 : 1).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| leverX | Lever X | Required. Finite number. |
| leverY | Lever Y | Required. Finite number. |
| forceX | Force X | Required. Finite number. |
| forceY | Force Y | Required. Finite number. |
| reverseNormal | Reverse Normal | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| signedMoment | Signed Moment | Required. Finite number. |
{
"input": {
"leverX": 2,
"leverY": 0,
"forceX": 0,
"forceY": 3,
"reverseNormal": false
},
"output": {
"signedMoment": 6
}
}Limitations and assumptions
- Lever and force vectors must share an origin/frame and compatible units; no anatomical axis or actual joint moment is inferred.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use verified anatomy and calibration, a consistent coordinate frame and a complete appropriate mechanical model for actual loading or clinical interpretation.
References
Similar or alternative tools
- Joint Moment Anatomical Axis Token
Transform a moment with a supplied axis sign.
- Force Plate Cross Axis Reference Sign
Apply supplied plate/laboratory force-axis signs.