A circular disc made of iron is rotated about its axis at a constant velocity `Omega.` Calculate the percentage change in the linear speed of a particle of the rim as the disc is slowly heated from `20^@C` to `50^@C` keeping the angular velocity constant. Coefficient of linear expansion of iron `=1.2 xx 10^(-5)C^(-1)`.

Explanation

To solve the problem, we need to calculate the percentage change in the linear speed of a particle on the rim of a circular disc made of iron when the temperature changes from 20°C to 50°C while keeping the angular velocity constant.

### Step-by-Step Solution:

1. **Understand the relationship between linear speed and angular speed**:
The linear speed \( v \) of a particle on the rim of the disc is given by the formula:
\[
v = r \omega
...