Concept
Resolving vectors — where it appears
Splitting a vector into components along chosen directions, which is a choice of description rather than a fact about the vector. Choosing the axes well is most of the skill: along and across an incline, the two equations separate, and along the horizontal and vertical they do not.
Named by 2 essays across one field — each of them below, with the objects they name alongside it.
The slope, and the two directions that make it easy
An inclined plane looks like a harder problem than a flat one. Split the weight into two components chosen to suit the slope and it becomes an easier one.
The same push, further out, and why that is a different quantity
A force is not enough to say whether something turns. What decides is where the line of the force passes, and the distance from the pivot to that line is the whole of the story.
Named alongside it
The objects these essays reach for when they reach for this one.
Free-body diagramMechanical advantageCentre of massFrictionIndependence of componentsMoment armNormal forceTorqueWork