PHY.2:4.3 - Construct the connection and its effect on the whole

For each connection that carries the target influence, identify what the connected parts share and what each can exchange. Write the interaction conditions together with the component laws. At an electrical junction, current conservation and common voltage connect the components; in a mechanical contact, the allowed motion and transmitted forces do that work. Other interactions need their own physical conditions.

Recover the state needed to continue the coupled behavior. The source may need a relative deformation, stored charge, field or direction of motion that neither isolated-component sketch retained. A.3.3.TR supplies the general state and joint-change construction. Here identify the physical means by which the additional state persists and affects the next change.

Check the physical restrictions that can defeat the construction. For an energy-carrying interaction, account for the relevant storage, exchange, dissipation and driving. A source that uses only passive dissipative elements cannot supply sustained amplification; an active source needs an identified supply. For a transport or switching mechanism, include the travel time, waiting law or constraint that changes the intended result. The useful restriction depends on the source, so follow it to the target consequence.

Use these restrictions to improve the construction. Add the missing coupling, replace an unsuitable element, change a boundary or keep a result limited to the regime the source can produce. If the target’s required relation conflicts with the source’s physical laws, choose another source or revise the hypothesis. This conflict is an informative result of construction.