The force applied to a lever, multiplied by the distance from the lever's fulcrum, multiplied again by the sine of the angle created, is described as torque. This is also known as "r cross f," or "force times fulcrum distance times sine theta."
The equation for torque is:
where F is the force vector and r is the vector from the axis of rotation to the point where the force is acting.
Torque Facts for Kids. Kiddle Encyclopedia.