Key words : circular rotate axis propeller turbine mobility journey (v) vehicle invention civilisation
Human beings have invented many important things so far. They have brought great civilization to the world through these inventions. Do you know which invention is the greatest? It is 'the wheel'.
A wheel is a circular object. It can rotate around its axis and help easy movement of things across a surface.
The wheels are, in fact, everywhere. They are on our cars, trains, planes, wagons and so on. Besides, they are on most factory and farm equipment. Fans, propellers, turbines are also other types of wheels.
So the wheel is very important. We cannot imagine modern life without wheels. But do we know exactly who made the first wheel?
Questions
difficult much circular important heavy first |
Although the wheel is a very (a) ------ invention, the history of its origin is unknown. Experts guess that the first wheel was developed from a circular object. The early man observed that a huge piece of stone could be rolled easily if it was (b) ------ in shape. Similarly, a heavy tree-trunk is (c) ------ to carry; but it can be rolled away with less effort. Even, a gigantic tree-trunk can be moved easily using other small and round trunks as rollers under it. Thus, early man took advantage of rolling objects and developed the (d) ------ wheel. Apart from its mechanical advantage, a wheel's mobility has contributed (e) ------ to the civilisation.
1. The wheel 2. A plain wheel 3. It 4. A propeller |
is has rotates | a type of wheel. around its axis. one of the simplest machines. wheels on vehicles and machines. helped in rapid progress of civilisation. |
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