Fulcrum

A fulcrum is the fixed point about which a lever rotates. Its position relative to the effort and load determines the lever’s mechanical advantage.

Lever: A rigid bar that rotates around a support to transmit or modify force. The fulcrum is the support around which a lever turns.
Axis of rotation: A line about which a rotating body turns. A lever’s fulcrum defines its rotation axis in a planar model.
Scissors: A hand tool with two pivoting blades used for cutting materials. The central pivot serves as the fulcrum for both lever arms.
First-class lever: A lever whose fulcrum lies between the effort and the load. This arrangement places the pivot between the two applied forces.
Torque: A measure of the turning effect produced by a force about an axis or pivot. Forces on a lever create opposing torques about its fulcrum.
Force: An interaction that changes or tends to change an object's motion. Effort and load act as forces whose effects are compared around the fulcrum.
Pliers: A hand tool with pivoted jaws for gripping, bending, or cutting objects. Their joint acts as a fulcrum between handles and jaws.
Second-class lever: A lever whose load lies between the fulcrum and the effort. The pivot sits at one end, with the load between it and the effort.
Moment arm: The perpendicular distance between an axis of rotation and a force’s line of action. A force’s moment arm is measured relative to the fulcrum.
Static equilibrium: A condition in which an object remains at rest because net force and net torque are zero. A stationary lever requires both force balance and torque balance.

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