22. ISO 80000-4 — Mechanics🔗

The second part specified in full is ISO 80000-4, Mechanics. Every item — all of 4-1 … 4-32 — is catalogued: mass and the densities, momentum, the force family, impulse and the moments, pressure and stress, the strains and elastic moduli, the viscosities, power and the energies, the flows, and action — each carrying its exact source as data: the part, the printed item designation, the principal quantity symbol, and the coherent SI unit symbol. Only citation locators are recorded; no normative content (definitions, remarks) from the licensed standard is reproduced. The defining mathematics of selected remarks is formalized in the sibling module Part4.DefiningRelations.

Mechanics is where the two theses of the calculus bite hardest. The standard's own quantities force the issues: a force family that is a specialization lattice; the textbook torque-versus-energy dimension collision (both M·L²·T⁻², the newton metre reserved for one and the joule for the other); and a web of defining relations that build mechanical quantities out of Part-3 space-and-time quantities — momentum from mass and velocity, pressure from force and area.

1. 22.1. Quantity-kinds and units of ISO 80000-4
2. 22.2. The force family: distinguishing kinds by measurement principle
3. 22.3. Dimension does not classify; the kind does — the torque/energy case
4. 22.4. The algebraic Remarks as kind-laws: mechanics built from space and time
5. 22.5. Item index — ISO 80000-4