Planar Force Balance Workbench
Combine arbitrary planar forces and free couples, or solve up to three signed unknown force magnitudes with exact balance checks.
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How to use Planar Force Balance Workbench
Sum horizontal/vertical forces and counterclockwise moments about the entered reference, solve independent unknown directions and verify every equilibrium equation.
- Use the example as the schema; replace its labels and entered model assumptions.
- Sum horizontal/vertical forces and counterclockwise moments about the entered reference, solve independent unknown directions and verify every equilibrium equation.
- Calculate, inspect the complete witnesses and limitations, then copy or download the JSON report.
Good to know
- 0–100 known forces, 0–100 free couples and up to 3 unknown forces. Inputs are decimal strings in meters, newtons and N·m, each magnitude at most 1 billion. Unknown directions must have exact squared length 1.
- Resultant mode requires an empty unknowns array; balance mode requires 1–3 independent unknown columns. Singular, underdetermined and inconsistent systems fail explicitly. Approximate direction cosines that do not square to exactly 1 are outside this exact subset. No contact/tension admissibility, structural design or safety verdict.
- Local calculation with no upload, input persistence or outside lookup. Model JSON is limited to 30,000 characters and 10,000 values. Decimal quantities are strings with up to six places; count fields use plain JSON integers. Exact fractions are capped at 8,192 bits. The complete JSON output is limited to 1,000,000 characters; approximate numbers preserve their stored values. Unsupported states fail explicitly.
Common questions
Does a negative solved magnitude mean the equations failed?
No. It reverses the declared unit direction. The exact force/moment equations can still balance, but whether a real cable, contact or support can supply that sign is a separate physical constraint not modeled here.
Are my model inputs saved or sent to a server?
No. This model runs in the current browser tab and creates a local JSON download. It does not save your input or call an external data service.
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