Model: 002 The Lever
The lever is another basic principle of mechanics. It consists of a rigid bar resting upon a point called the fulcrum. The points are arranged in model 1 as in pliers and shears, model 2 as in a shovel, model 3 as in the wheelbarrow. The wheel and axle, and pulley are modifications of a lever.
[Virginia Downward & William M. Clark, 1930]

[Editor's Note: The use of the so-called 'simple machines' of the screw, lever, inclined plane, etc goes back to the Greeks and the school of Aristotle. Their use is based on the idea of machines as force transformation devices. This view of the machine was replaced by the Paris school of kinematics in the Ecole Polytechnique around 1800. A machine is viewed as a motion changing device. In Reuleaux's scheme, the 'simple machines' are parts of kinematic mechanisms or machine elements. However the 'simple machine' concept still persists in elementary school texts on machines and physics in the USA. FCM]

Francis Moon 2005-00-00

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