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Illustration of a lever with fulcrum F. W represents the weight lifted, P is the force that does the lifting, D is the distance from the fulcrum to the point of application of the force, and d is the distance from the fulcrum to the point where the weight is attached. In all possible relations of the fulcrum, weight, and force the following proportion holds: P:W = d:D.

Lever and Fulcrum

Illustration of a lever with fulcrum F. W represents the weight lifted, P is the force that does the…

Illustration of a hammer being used as a lever. F represents the fulcrum.

Hammer Used as a Lever

Illustration of a hammer being used as a lever. F represents the fulcrum.

Illustration of an ordinary steel-yard being used as a lever. F represents the fulcrum. Weight P is used to balance weight W.

Steel-yard Used as a Lever

Illustration of an ordinary steel-yard being used as a lever. F represents the fulcrum. Weight P is…

Gulliver gets a boat ready to sail to England.

Man flipping boat

Gulliver gets a boat ready to sail to England.

Illustration of a hydraulic machine. "A principle known as Pascal's Law states that pressure exerted on a liquid in a closed vessel is transmitted equally and undiminished in all directions." If a, A, p, and P respectively represent the areas and pressures, then the following proportion holds: a:A = p:P.

Hydraulic Machine Exerting Pressure

Illustration of a hydraulic machine. "A principle known as Pascal's Law states that pressure exerted…

A tool used for cutting metals. "a and c, levers connected by a link bar b, and respectively pivoted at f and f1 to the frame e. By the arrangement of the levers the movable blade d, attached to c, acts with a strong purchase in combination with the stationary blade d1, rigidly attached to the frame e." —Whitney, 1889

Purchase Shears for Cutting Metal

A tool used for cutting metals. "a and c, levers connected by a link bar b, and respectively pivoted…