How is the mechanical advantage of a lever calculated?

The mechanical advantage of a lever is calculated using the ratio of the length of the effort arm to the length of the resistance arm. This concept is rooted in the principle that levers amplify input force, allowing a smaller force applied at the effort arm to lift a larger load at the resistance arm.

In this context, the effort arm refers to the distance from the fulcrum (pivot point) to where the input force is applied, whereas the resistance arm is the distance from the fulcrum to the point where the load is applied. By dividing the length of the effort arm by the length of the resistance arm, you effectively determine how much the lever multiplies the force applied. A longer effort arm increases the mechanical advantage, meaning less effort is required to lift the same load, illustrating the efficiency that levers provide in simple machines.

The other options do not accurately represent the correct calculation for mechanical advantage, as they either reverse the necessary ratio or introduce irrelevant components that do not pertain to the fundamental mechanics of levers.