What is a machine?
A machine is any device that does work. Machines make our lives easier because they reduce the amount of energy, power, and time we need to get one thing done by magnifying our input force.
A machine can increase the magnitude or the distance of a force but not both at the same time.
Machines come in many sizes, shapes and forms. Some machines are very simple in its makeup and use whilst others are very complex. For example, a spade is a machine (a simple machine), and a space shuttle is a machine too (a complex machine).
For this lesson, we shall be looking at simple machines.
Consider the illustration below:
To bring the load (wagon with a mound of dirt in it) to the lower surface, a person has to carry that carefully. That is a lot of muscle work. To make that easier, we can just put a ramp there, and just give the wagon a little push — right? Yes, and then the load will just slide down on its own.
In the example above, we have used a very simple trick of a simple machine to bring down that load of dirt — easily!
Here is another scenario: A bulldozer at work! Take note of the simple machine units (levers, wheel and axle, wedge) that are combined to build a complex machine.
To push a mound of dirt on a piece of land, it can take a person with a shovel a lot of time and energy to do so. However one person with a complex machine can do that work in no time. Here, the complex machine, which is a complex combination of simple machine units, uses mechanical energy and electrical energy to do that job. It is not the same as a simple machine. This bulldozer is an example of a compound or complex machine.
Now let us take a look at some simple machines types.