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Let's Lift an Elephant

Pulley and Wheel-axel

In hospitals, you must have seen that a slope is made besides the normal stairs. Do you know why the slope is made there?

It is used for carrying patients in a wheel chair. The slope besides the stairs is an example of inclined plane. It is the simplest form of machine mainly used for lifting heavy load up to a small height. An inclined plane can be made up of a wooden plank or of concrete. One end of the plank is kept at a certain height and the other end is kept at the ground level so that the plank makes an angle with the ground. Now, some heavy load can be easily rolled over the plane of the plank.

 Do you know? You must have seen trucks full with heavy loads. Do you know how the trucks are loaded?

 ­ If you visit a hill station, then you will notice that the hill roads are winding. What is the reason behind that?
 Before going into the answer, let us understand the mechanical advantage of an inclined plane. An inclined plane reduces the force required to raise an object to a height by increasing the distance the object has to travel. Therefore, for an inclined plane, the mechanical advantage is measured by the ratio of the length of the inclined plane (l) to the topmost height of the plane (h).

You can easily make out from the equation that for a certain height, we can obtain a greater mechanical advantage by increasing the length of the inclined plane. Now, can you answer why the roads are made winding through hills?

Which one is easy, fitting a screw or hammering a nail in the wood?

A screw is a rotating (winding) inclined plane made up of iron strips. The threads on the screw are made in such a way that when fitted …

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