LEVER

The simplest machine, and perhaps the one with which you are most familiar, is the lever. A seesaw is a familiar example of a lever in which one weight balances the other.balances the other.
You will find that all levers have three basic parts:the fulcrum (F), a force or effort (E), and a resistance(R). Look at the lever in pic . You see the pivotal point (fulcrum) (F); the effort (E), which is applied at a distance (A) from the fulcrum; and a resistance (R), which acts at a distance (a) from the fulcrum. Distances A and a are the arms of the lever.

CLASSES OF LEVERS:.
The location of the fulcrum (the fixed or pivot point) in
relation to the resistance (or weight) and the effort
determines the lever class

 

Crowbars, shears, and pliers are common examples of first class of levers

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The wheelbarrow in  is a good example of a second-class lever. If you apply 50 pounds of effort to
the handles of a wheelbarrow 4 feet from the fulcrum (wheel), you can lift 200 pounds of weight 1 foot from the fulcrum. If the load were placed farther away from the wheel, would it be easier or harder to lift? Levers of the first and second class are commonly used to help in overcoming big resistances with a relatively small effort.

Sometimes you will want to speed up the movement of the resistance even though you have to use a large amount of effort. Levers that help you accomplish this are in the third class of levers.

Third class lever

So our arm action is third class lever ,in the next post we will see about direct relationship between the length
of the lever arm and the force acting on that arm. here is the video from you tube just for visual understanding

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