A $2 \mathrm{kg}$ steel rod of length $0.6 \mathrm{m}$ is clamped on a table vertically at its lower end and is free to rotate in the vertical plane. The upper end is pushed so that the rod falls under gravity. Ignoring the friction due to clamping at its lower end, the speed of the free end of the rod when it passes through its lowest position is $\_\_\_\_\_\_ \mathrm{m} {\mathrm{s}}^{-1}.$
(Take $g=10{ \mathrm{m} \mathrm{s}}^{-2} )$

The position of the centre of mass of a uniform semi-circular wire of radius $R$ placed in $x-y$ plane with its centre at the origin and the line joining its ends as $x-$axis is given by, $\left(0, \frac{xR}{\pi }\right).$ Then, the value of $\left|x\right|$ is $\underline{ }.$

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Moment of inertia of a circular disc of mass $M$ and radius $R$ about $X,Y$ axes (passing through its plane) and Z-axis which is perpendicular to its plane were found to be $I_{\mathrm{x}},I_{\mathrm{y}}$ and $I_{\mathrm{z}}$, respectively. The respective radii of gyration about all the three axes will be the same.

Reason R: A rigid body making rotational motion has fixed mass and shape. In the light of the above statements, choose the most appropriate answer from the options given below: