|
The lever is a simple machine made
with a bar free to move about a fixed point called a fulcrum. The lever consists of three parts. The fulcrum,load,and a rod.Levers
are classified into three classes. The First Class Lever, Second Class Lever and the Third Class lever. The first class lever is the one
with the fulcrum in the center. In this example, the fulcrum is the edge of the tin of biscuits. The load is much more
nearer to the fulcrum than the effort. Therefore we can use a small force to pull out the nail compared to pulling it
out directly without using the lever. Also notice that the lever changes the direction of force. As the handle of the
spoon goes down, the lid goes up. For the second class lever, the bottle cap, which is the load, is in the
centre. For the second lever, whenever the load is nearer to the fulcrum, the effort needed to lift the load will be less.
The third class lever however, is the disadvantageous one. It has the effort in the center. No matter how close or how far
the load is from the fulcrum, the effort used to lift the load, has to be greater than the load!
|
The Lever