The picture displayed shows a lever. 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 (see smiling triangle), load (see smiling box) and a rod (see brown plank). Levers are classified into three classes. The First Class Lever, Second Class Lever and the Third Class lever. The only difference between them is the location of the fulcrum.
Levers help you move items that are very
heavy. In the First Class lever the fulcrum is located in the middle. The load
is on one end and the force is on the other. (crowbar) Second Class the
fulcrum is on the end, the resistance force, the load, is in the middle, and the
effort is at the other end. (wheelbarrow) The Third Class fulcrum is on the end
of one side, the effort force is in the middle, and the resistance force, the
load, is at the the top. (baseball bat)
Levers are easy to spot because they help us
in our lives. Some examples are: see-saw, claw hammer, crow bar, bottle opener,
Piano keys, and car jacks.