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A balance scale holding 5 pounds on the left and 3 and 2 pound weights on the right showing 3+2=5.

Addition Scale

A balance scale holding 5 pounds on the left and 3 and 2 pound weights on the right showing 3+2=5.

"When two bodies of equal weight are connected by a rod, the centre of gravity will lie in the middle of that rod. When two bodies of unequal weight are so connected, the centre of gravity will be nearer to the heavier one. These principles are illustrated [here], in which C represents the centre of gravity." —Quackenbos 1859

Center of Gravity of Rod with Weights

"When two bodies of equal weight are connected by a rod, the centre of gravity will lie in the middle…

Two spheres of iron or other heavy material, connected by a short bar for a handle; used as a weight for swinging in the hands.

Dumb-bells

Two spheres of iron or other heavy material, connected by a short bar for a handle; used as a weight…

"A bar with weights attached that is in equilibrium." -Avery 1895

Bar and Weights in Equilibrium

"A bar with weights attached that is in equilibrium." -Avery 1895

"A bar with weights attached that is in equilibrium." -Avery 1895

Bar and Weights in Equilibrium

"A bar with weights attached that is in equilibrium." -Avery 1895

Two students drawing geometrical shapes on the chalkboard. A student is also using a scale while students sitting at desks take notes.

Geometry

Two students drawing geometrical shapes on the chalkboard. A student is also using a scale while students…

An illustration of a lever with weights m and n with distances a and b from fulcrum. Illustration could be used with proportions.

Lever Balanced on fulcrum With Weights

An illustration of a lever with weights m and n with distances a and b from fulcrum. Illustration could…

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…

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…

"...represents a very valuable attachment for the whirling table. A ball of known mass slides on a horizonal wire. To this ball is attached a flexible cord that turns around a pulley at the bottom, divides into two, passes over the pulleys at the top, and carries adjustable and slotted disk weights." -Avery 1895

Attachment for the Whirling Table

"...represents a very valuable attachment for the whirling table. A ball of known mass slides on a horizonal…

A cylinder or roller for raising weights, turned by a crank or lever, with a rope or chain attached to the weight.

Windlass

A cylinder or roller for raising weights, turned by a crank or lever, with a rope or chain attached…