leviers
Levers, or levier in French, are simple machines consisting of a rigid bar that rotates around a fixed point called the fulcrum. The bar carries a load on one side and an effort on the other. When the lever is used, the user applies a force (the effort) at a given distance from the fulcrum, raising or moving a load at another distance. The relationship between forces is governed by torque: F_e × d_e = F_l × d_l, where d_e and d_l are the distances from the fulcrum to the points of effort and load. The lever’s mechanical advantage equals d_e/d_l, assuming negligible friction.
They are classified into three main classes. Class I levers have the fulcrum between the effort and
History and significance: Levers are among the oldest known simple machines. Their understanding dates to ancient
Applications and design: Levers are chosen for desired trade-offs between force, speed, and travel distance. Real-world