What Is a Machine?

1.  What is a Machine

·       A device consisting of fixed and moving parts that modifies mechanical energy and transmits it in a more useful form.

·       A simple device, such as a lever, a pulley, or an inclined plane, that alters the magnitude or direction, or both, of an applied force; a simple machine.

Although technology is constantly changing, it's helpful to remember that all machines are made of the same basic parts. The term simple machine is used to refer to devices that have few moving parts, if any, but use energy to work. If two or more simple machines are joined together to make a single mechanism, the resulting device is known as a complex machine.
The six simple machines are the screw, inclined plane, wedge, lever, pulley, and wheel and axle. Within this group, you can break down simple machines into two smaller categories. The inclined plane, wedge, and screw are dependent on the vector resolution of forces, while the lever, pulley, and wheel work because there is equilibrium of torques.
An inclined plane is a slanting surface that connects a lower level to a higher level. A wedge is an object with a slanting side that ends in a shape point to help you cut material apart. A screw is essentially an inclined plane wrapped around a pole, making it possible to hold materials together.

A lever is a bar resting on a fulcrum that can lift or move loads. A pulley is a wheel with a groove between two flanges around its circumference and a cable, belt, or rope running inside the groove. A wheel and axle is a modification of a pulley in which a wheel is attached to a shaft, such as on a pair of roller skates.

The idea of a simple machine was first discussed by the ancient Greek philosopher Archimedes. However, the complete theory of a simple machine as an object that transforms energy is actually attributed to Italian scientist Galileo Galilei in his 1600 publication of Le Meccaniche (On Mechanics).

While the traditional definition of a simple machine includes six separate machines, it is interesting to note that not everyone agrees with this theory. For example, there are people who argue that both a pulley and a wheel and axle can be viewed as unique types of levers. There are also people who believe that hydraulic systems are a type of simple machine as well, since they provide amplification of force.