A lever is a simple machine which has three basic components – fulcrum, load and effort. There is a load which needs little or more effort to lift. The fulcrum tends to be a fixed point whose position decides how much effort/force is required to lift the load.
Based on the position of the fulcrum, levers are classified into three types – first class lever, second class lever and third class lever.
Devices used by pilots to control an airplane.
When the fulcrum is located between the load and the effort, it is said to be first class lever. See saw, crow bars, cutting pliers, wrecking bars and oar used by sailor to row boats are good examples of first class levers.
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When the load is in between the fulcrum and effort, it is called second class lever. Wheel barrow is one good example of second class lever. The first and second class levers are used to work on heavy objects with less effort and can also magnify the applied force.
The third class levers are not suitable for heavy jobs but used for gaining speed. Movement of our arm is an example of third class lever where the effort is applied in between the fulcrum and load. The biceps muscle applies force, elbow is the fulcrum and hand carries the load. Crane is another example of third class lever.
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