Question

Why are sleepers used below the rails?

Answer 1

Hint: We have observed if we carry a heavy bag on our shoulders but with narrow straps, we feel tired very fast but if the same bag has broad straps then it becomes quite easy to carry it to a long distance.

Complete step by step answer:
Sleepers are usually laid below the rails to spread the weight of the moving train over to a larger area. This is done to increase the area so that the pressure exerted by the rail gets decreased. This is following Pascal’s law of pressure.
From Pascal’s law \[P=\dfrac{F}{A}\]
It is evident from the above equation that when Area is increased, the pressure decreases and hence the weight of the passing train is spread over a large area which decreases the pressure and the track may not sink into the ground.
Thus providing safety to the movement of the trains on the rail tracks.

Additional Information:
Not only in solids but also in liquids Pascal’s law is equally valid. In liquid it states that pressure exerted on a liquid is transmitted equally in all the directions.

Note:
This is just another useful application of Pascal’s law of pressure. Pascal’s law of pressure is so much evident in our daily life. For example, when we are using knives to cut fruits or vegetables the contact area of the knife with the object is made extremely thin. Following the law, the area decreases and which in turn increases the force acting and hence aids in easily cutting the fruits or vegetables.