Moment arm

A moment arm is the shortest perpendicular distance between the line of action of a force and the axis or fulcrum of rotation. It determines how effectively a force creates rotational movement or torque. For example, if you try to turn a bolt with a wrench, a longer wrench increases the moment arm, making it easier to twist the bolt because the force is applied farther from the center. In essence, a larger moment arm amplifies the turning effect of a force, enabling easier or more powerful rotation with the same amount of effort.