Understanding how machines work is very useful to everyone. The physics behind their function and working principle helps all to use them more efficiently. Machines help us perform a big job with very minimal effort which is why they are super useful in day to day living.
Consider a tractor which is one of the machines used to perform work. A tractor could be used to pull a heavy load such as a giant log of wood, carry heavy equipment or even push down a big rock. One person driving the tractor could perform all these work without breaking a sweat. But if it was to be performed manually, it would take so many people days to accomplish the same task.
How a Lever Machine work
There are many types of simple machines, Lever is one of them. The major working principle of a liver is based on three components as explained below:
Fulcrum: The fulcrum is an important component of a Lever and other simple machines. It is the central point of support for the machine to handle the load. The fulcrum provides balance, support and point of rotation needed for the machine to overcome its load. Depending on the class of lever, the fulcrum can be located between the load and effort.
Load: The load represents the object being moved, carried or lifted. The load provides some form of resistance which the machine is expected to overcome. Usually, the load is much bigger that when handled manually, it takes considerable time and effort to work it out. But the lever machine uses a fraction of the force needed by manual labor to perform the work.
Effort: The force applied on the machine to overcome the load is know as effort. Depending on the nature of the load, the effort could be the force needed by the machine to lift a heavy object, pull a big tree, or crush a nut. Usually, small effort is comparatively needed to overcome a large load.
Classification of Lever Machines
The position of the fulcrum relative to the load and effort led to at least 3 classifications of a lever. There are as follows:
First class levers: In first class levers, the fulcrum or pivot is found at the center of the machine. That simply means that the Load and effort at either ends of the machine while the fulcrum is at the middle. Check the image below:
There are many examples of first class levers. They include the Crow bar used by carpenters to pull up nails stuck in a wood. Check the first picture at the top. Another good example of a first class lever is a plier. Notice in the illustration below that the fulcrum of the plier is at the middle, while the load and effort are at either ends of the plier.
Second class levers: In a second class lever, the fulcrum is located at one extreme end of the machine. The effort is applied at the other end of the machine while the load is found at the middle. Thinking about an example, there are many of them. I have illustrated a Wheelbarrow below which is a great example of a second class lever. Take a look.
Apart from a wheelbarrow, there are many other examples of second class levers like a bottle opener, nutcracker and many others.
Finally
Understanding how simple machines work is essential for their efficient use. I have given a great example with lever as a simple machine. They provide a good mechanical advantage based on the type of load they are meant to bear and the effort applied.
In the next class, I will explain the third class levers with example. Then we will do some calculations to know the efficiency of simple machines and their mechanical advantage.