Formula Law of the Lever Effort arm length Load force Load arm length
$$F_1 \, l_1 ~=~ F_2 \, l_2$$ $$F_1 ~=~ \frac{ F_2 \, l_2 }{ l_1 }$$ $$l_1 ~=~ \frac{ F_2 \, l_2 }{ F_1 }$$ $$F_2 ~=~ \frac{ F_1 \, l_1 }{ l_2 }$$ $$l_2 ~=~ \frac{ F_1 \, l_1 }{ F_2 }$$
Effort force
\( F_1 \) Unit \( \mathrm{N} \) Force acting on the effort arm. Effort arm is a part of the lever. If a force is applied to the effort arm, the load arm with a mass on it is lifted.
Effort arm length
\( l_1 \) Unit \( \mathrm{m} \) Length of the effort arm is the length measured from the point of application of the effort force to the pivot point.
Load force
\( F_2 \) Unit \( \mathrm{N} \) Load force is a force acting on the load arm. Load arm is the part of the lever on which, for example, the mass to be lifted is placed. In this case, the load force \(F_2\) corresponds to gravity force.
Load arm length
\( l_2 \) Unit \( \mathrm{m} \) Length of the load arm measured from the point of application of the force \(F_2\) to the pivot point.