Lesson
Angular Kinetics
TORQUE and its EFFECT on LEVERS and EQUILIBRIUM
TORQUE (aka MOMENT): The rotary effect created by an applied force OR
a Rotary Force (angular equivalent of linear force)
It is the product of a force and the force’s moment arm
(MOMENT ARM = perpendicular/shortest distance from the force’s line of action to the object’s axis of rotation) T = F x d^
In the human body, the moment arm for a muscle with respect to a joint center is the
perpendicular distance between the muscle’s line of action and the joint center.
For any given muscle, the moment arm is largest when the angle of pull on the bone is
closest to 90º. Thus changes in length of moment arm affect the joint torque a muscle
can generate.