Question

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

Answer 1

(a) Air is highly compressible, so when air is filled in the tyres, it provides damping and adjusts easily to get the required friction depending upon the surface conditions.

(b) Steel is used for railway lines because it has high tensile strength and appropriate hardness. It has resistance to internal and surface cracks.