A lever is a simple machine consisting of a rigid beam or rod pivoted at a fixed hinge or fulcrum. The lever is divided into three types based on the locations of the fulcrum, load, and effort. The three types of levers are:
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First-class lever: The fulcrum is located between the load and effort. Examples of first-class levers include pliers, scissors, and a see-saw.
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Second-class lever: The load is located between the fulcrum and effort. Examples of second-class levers include a wheelbarrow, bottle openers, and a nutcracker.
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Third-class lever: The effort is located between the fulcrum and load. Examples of third-class levers include a shovel, fishing rod, and cooking tongs.
Levers rely on torque for their operation, which is the amount of force required to cause an object to rotate around its axis or pivot point. If the distance from the effort to the fulcrum is greater than the distance from the load to the fulcrum, then the lever has a mechanical advantage. In other words, a long distance from the effort to the fulcrum and a short distance from the load to the fulcrum will allow a small effort to move a large load.
