# Machines: speed and force multipliers

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A machine is a device that makes work easier by transmitting or transforming energy. They have been used since ancient times to help people move heavy objects, bring substances like water from one place to another and fasten materials to one another in construction. Today, machines are used for a huge number of tasks, including transportation, communication and entertainment.

Machines can make work easier by decreasing the force necessary to move an object or increasing the speed of an object. They can also make work easier by changing the direction in which force must be applied to do work. Different types of machines accomplish this in different ways. Examples of machines are levers, inclined planes, wedges, wheels and axles, gears and pulleys. These different types of machines will be discussed in depth in later chapters.

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## Force multipliers and speed multipliers

Machines can make work easier by reducing the amount of force necessary to move an object or increasing the speed of an object relative to the force applied to it.

Force multipliers are devices that reduce the amount of force necessary to move an object. Force multipliers are useful for lifting heavy objects or doing other things that require large amounts of force. Some examples of force multipliers are inclined planes and most levers.

Speed multipliers are devices that increase the speed of, or distance travelled by, an object. Although more force than usual is required to move the object in these cases, the extra force is changed into more kinetic energy. Speed multipliers are useful when an object needs to move a further distance or at a higher speed. Some examples are wheels and axles and third class levers.

Simple and complex machines
Machines can be either simple or complex. Simple machines are machines that only use one type of machine, such as a lever or an inclined plane. Complex machines are machines that use multiple types of machines together. A door, for example, uses both a wheel and axle (the doorknob) and a lever (the door itself).

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## Early machines

The first machines were made by early humans. They included weapons for hunting food, knives for cutting meat and skins, and shovels for digging in the earth for roots. As technology used by humans progressed, tools became more sophisticated. Agriculture was made possible by tools such as the plough and irrigation devices.

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The earliest machines were simple machines. As human society became more complex, however, more complex machines were built.

## Everyday machines

In modern times, most people use machines of some sort every day. Imagine waking up in the morning. What do you do? Do you fasten your pants with a zipper? Do you use a doorknob to open your bedroom door? Do you use a knife to spread butter on your toast? A zipper, a doorknob, a door and a knife are all examples of machines.

Without machines, life would be very different. We would not have computers, cars or even houses. In fact, we would not even have primitive tools like bows and arrows or ploughs. Machines are an important example of technology, or devices that make day-to-day life easier.

Chapters:

## ToolBox

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