PHY.6:4.1 - Choose the consequence and physical participants

State what the answer will let someone interpret, choose or do. Identify the quantity, interval and preparation that matter. A peak response, a total transferred amount and a settled value can require different accounts of the same arrangement.

Choose the physical participants and their boundaries at a useful resolution. Locate the interactions that can affect the answer, including supports, surrounding media and measurement when relevant. Distinguish a quantity stored in a participant from a quantity passing through its boundary. Include storage in a contact or field when omitting it would change the consequence.

Use PHY.5 to resolve a consequential choice of scale or omitted interaction. A spatial field, a few aggregate variables and individual particles are possible descriptions; their physical adequacy depends on the question and regime.