Lever
From prehistoric times levers were used for cultivation, excavation, and moving large objects. Such implements as hoes, slings, and oars were conceived and constructed to enhance human effort. T...
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Levers
A lever is a rigid bar or rod that can pivot about a fixed position. This fixed position is called a fulcrum. Examples of levers include a seesaw, a crowbar, and a bottle opener. A lever is a t...
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