Find the $x$ coordinate of the centre of mass of the books shown in the figure. Every book has mass $m$.

Explain the theoretical method for the estimation of the centre of mass of a solid body.

The linear mass density of a rod of length $L$ varies as $\lambda = kx^2$,where $k$ is a constant and $x$ is the distance from one end. The position of the centre of mass of the rod is:

Three identical spheres,each of mass $1 \ kg$,are placed touching each other with their centres on a straight line. Their centres are marked $K, L$,and $M$ respectively. The distance of the centre of mass of the system from $K$ is

Three bodies each of mass $1 \,kg$ are situated at the vertices of an equilateral triangle of side $1 \,m$. The $x y$-coordinates of the centre of mass of the system are:

$A$ particle of mass $m$ is moving in the $xy$-plane at a certain height from the ground along the $x$-axis. It suddenly explodes into two fragments of masses $m/4$ and $3m/4$. At that instant,the smaller fragment is at $y = 15 \ cm$. At this instant,the larger fragment will be at $y = $ ........ $cm$.