Torque
The rotational equivalent of linear force, measuring the effectiveness of a force in causing angular acceleration about an axis.
Governing formula
τ = r × F = r F sin θ
SI unit
N·m
In depth
Torque depends on force magnitude, distance from pivot (lever arm r), and angle of application. Maximizing lever arm r maximizes rotational force.
Examples in the real world
Using a long-handled wrench to loosen a tight bolt easily, or pushing a door near its outer handle rather than near its hinges.