Bold Kids

Machines Effect On Force 4th Grade Children's Science Book Bold Kids

A machine is an instrument which can transform energy into something else. Most machines use complex elements. Various types of machines accomplish the same task in different ways. Some examples of machines include doors, wheels and axles, pulleys, inclined planes and gears. The first known machines were simple devices. They were used by early humans to make weapons for hunting and digging roots. Later, they were used in agriculture. Today, they are used for a wide variety of tasks.
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