Stories, accumulations, constraints

Physics is about stories grounded in evidence, reliable enough to act on. About what will-be and what may-be: about prediction and possibility(and so also about what may-not-be, or impossibility). To make quantitative predictions rely on relationships between quantities: these relationships are either accumulation or constraint, or a combination of these two kinds. To figure out what could happen, find frozen moments (maybes in a possibility space). This is reasoning with constraints.

Accumulating or constraining

Of all the things you could imagine happening, only some are actually possible, and these depend on what’s the case now. (You’re picking out possibilities in phase space.)

Conservation laws are examples of constraints. Mass is conserved; momentum is conserved; energy is conserved. There is a common pattern of reasoning across these three that could be fruitful.

Thinking within the box

To figure out what will happen, reason with accumulations.

kinematics through accumulations

There's a range ;of examples of this reasoning in the sequence above – but for now, this thread is all about thinking with boxes applied to thinking with constraints.