Question

Why is the iron rim heated to red hot,before mounting it on a wooden wheel

Answer 1

the metal rim to be put on a cartwheel is designed to have a smaller diameter than that of the wheal. when the rim is heated it becomes red hot expands and slips On The Wheel easily when it is cooled it contracts and grips the wheel firmly.

Answer 2

Metals expand on heating and contract on cooling. This expansion and contraction of a metal is a reversible change. The metallic rim used is slightly smaller in diameter than the wheels .On heating the rim expands. And can easily lie on the wheels. When the rim cools, it contract and press tightly on to the wheels.




Hope it helps