A horizontal disc is freely rotating about a vertical axis passing through its centre at the rate of `100rpm`. A bob of wax of mass `20g` falls on the disc and sticks to it a distance of `5cm` from the axis. If the moment of inertia of the disc about the given axis is `2xx10^(-4) kgm^2`, find new frequency of rotation of the disc.

Explanation

To solve the problem, we will use the principle of conservation of angular momentum. The angular momentum before the wax bob sticks to the disc must equal the angular momentum after it sticks.

### Step-by-Step Solution:

1. **Convert the initial angular speed from rpm to rad/s**:
\[ \omega_i = 100 \, \text{rpm} = 100 \times \frac{2\pi \, \text{rad}}{1 \, \text{min}} = 100 \times \frac{2\pi}{60} \, \text{rad/s} = \frac{100 \times 2\pi}{60} \approx 10.47 \, \text{rad/s} \]
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