Lever arm

A lever arm is a perpendicular distance from a pivot point or fulcrum to the line of action of a force applied to an object. It determines the leverage or mechanical advantage in a lever system—longer lever arms allow smaller forces to produce greater rotational effect, or torque, making it easier to move or turn objects. In simple terms, think of a seesaw: the distance from the center to where you sit is the lever arm; the longer it is, the easier it is to lift your side by applying less force.