lever principle formula: power × power arm = resistance × resistance arm is a labor-saving lever when the distance from the power point to the fulcrum of the lever is greater than the distance from the resistance point to the fulcrum, an equal-arm lever when the distance from the power point to the fulcrum of the lever is less than the distance from the resistance point to the fulcrum.

Labor-saving levers include nail clippers, vises, doors, windows, scissors and wrenches. Lever, engine rocker

Equal arm lever: seesaw, balance,

Effort lever: arm, arm strength fitness equipment, chopsticks, tweezers, fishing rod, boat pulp.