Question

During fixing the metal rim on a wooden wheel of a cart, which of the following is
used to contract the metal rim?
A. Cold water is poured over the rim.
B. Hot water is poured over the rim.
C. Metal rim is placed in an ice bath.
D. Metal rim is placed in the steam bath.

Answer 1

Hint: For longer life and better holding capacity the size of the metal rim is always kept gradually smaller than the wooden wheel. Before placing it over the wheel its contraction is required so as to achieve the smaller size.

Step by step answer: Now, let’s discuss the fixing of metal rim on a wooden wheel of a cart.
It must somehow be connected to the wooden cart wheel in order for the rim to work in an efficient manner. And, no matter how rough it is, it must not fall away. If a flat iron or steel band is made into a hoop, it will also expand when heated.
The hoop is heated, it then extends considerably and can be mounted around the wheel. It then cooled rapidly, shrinks back to its normal, unheated size and so tightly grips the wheel that it cannot be removed.
They are heated because, when we heat the iron rim the iron rim will expand this process this process is called expansion. When it expands its size will also be expanding and it could fit in the wooden wheel after fitting it. We have to cool down the iron rim so it will fit very tightly.

Therefore, the correct answer is A.

Note: Accurately circular metal wheels on a steel rail have low rolling resistance. A tire would be compressed with every rotation, which consumes energy. So metal wheels are more efficient and consume less energy.