Calculate rotational `K.E.` of earth about its own axis, taking it to be a sphere of mass `6 xx 10^(24) kg` and radius `6400 km`.

Explanation

To calculate the rotational kinetic energy (K.E.) of the Earth about its own axis, we will follow these steps:

### Step 1: Understand the formula for rotational kinetic energy
The rotational kinetic energy (K.E.) of a rotating object is given by the formula:
\[ K.E. = \frac{1}{2} I \omega^2 \]
where \( I \) is the moment of inertia and \( \omega \) is the angular velocity.
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