Concept
Method of sections
2 essays name this object, across one field. What follows is each of them, and the objects they name alongside it.
The free body is a choice, and choosing it well is the whole skill
Cutting a structure open is not a step in the method. It is the method — and where the cut is made decides whether the answer takes one line or twenty.
Answering one question without solving the rest
A truss of fifty members can be interrogated about one of them. Cut through three, take moments about the point where two of them meet, and the third falls out in a single line.
Named alongside it
The objects these essays reach for when they reach for this one.
Free body diagramBoundaryChord forceEquilibriumInternal forcesLever armMoment centreMoment equilibriumNewton's third lawPanel shearReactions