1. Torque is a vector quantity that determines the ability of a force to introduce rotation. It is calculated as the product of the force and the lever arm (perpendicular distance from the axis of rotation to the line of force). 2. Torque depends on three factors: the magnitude of the applied force, the distance from the point of application to the pivot, and the angle of the applied force. 3. The lever arm used in torque calculations must be the perpendicular distance from the axis of rotation to the line of action of the force.