A disc is recast into a hollow sphere of having half radius? How moment of inertia will be affected by the change of shape?

Explanation

To solve the problem, we need to analyze the moment of inertia of a disc and a hollow sphere, and how the change in shape affects it.

### Step 1: Moment of Inertia of the Disc
The moment of inertia \( I_0 \) of a solid disc about its central axis is given by the formula:
\[ I_0 = \frac{1}{2} m r^2 \]
where \( m \) is the mass of the disc and \( r \) is its radius.
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