When a body is under pure rolling, the fraction of its total kinetic energy which is the purely rotational is 2/5. Identify the body.

Explanation

To solve the problem, we need to identify the body based on the given fraction of its total kinetic energy that is purely rotational when it is under pure rolling. The fraction is given as \( \frac{2}{5} \).

### Step-by-Step Solution:

1. **Understand the Kinetic Energy Components**:
- The total kinetic energy (KE) of a rolling body consists of two parts: translational kinetic energy and rotational kinetic energy.
- The formulas are:
- Rotational Kinetic Energy (RKE): \( KE_{rot} = \frac{1}{2} I \omega^2 \)
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