Question

Explain why :
(a) air is used to inflate tyres.
(b) steel is used to make railway lines.

Answer 1

(a) Air is used to inflate tyres because air can take the shape of any substance that it is pushed into, as there are large inter-molecular spaces present in air. Thus, when air is filled in a tyre, its particles distribute themselves evenly by diffusion inside the tyre, giving it a proper balance. Liquid can be filled in a tyre but it will exert more pressure than the atmospheric pressure and there will be chances of tyre getting burst. Besides, it will unnecessarily increase the weight of the vehicle.

(b) Steel is used to make railway lines because the particles of steel have fixed positions and show no free movement. This ensures that there will be no change in the shape of the railway lines, which makes it safe to travel.