What does the term 'force arm' refer to?

The term 'force arm' specifically refers to the perpendicular distance from the axis of rotation to the line of action of the force. This concept is crucial in understanding torque, as torque is calculated by multiplying the magnitude of the force by its force arm. The greater the distance (or force arm), the greater the torque produced by the applied force, which highlights its importance in biomechanics and physical training.

The other choices do not accurately capture the definition of 'force arm.' The length of the mass from the axis refers more to the lever arm or radius than the specific geometry of the force application. The distance from the point of impact to the center of mass speaks to the interaction of forces but lacks the clear definition tied to torque and rotation. Lastly, the total distance traveled by an object relates to motion but does not pertain to the specific mechanics governing how force is applied around a pivot point.