What is a turning or twisting force?

• A. Torque
• B. Force
• C. Moment
• D. Velocity

Answer: (A)

A turning or twisting force is torque. It’s the measure of how strongly a force tends to rotate an object about an axis. The effect depends on how far from the axis you push (the lever arm) and the angle of the force relative to that lever arm—the farther away and more perpendicular the force is, the greater the turning effect. If you push directly toward or away from the pivot, or right through the pivot, there’s no rotation produced, so the torque is zero. Torque is described by the relation with the lever arm and force, and its unit is Newton-meters. Velocity is about motion, not rotation about an axis, and while “moment” is sometimes used to mean torque, the standard term for the turning force is torque.