A $2\ kg$ block slides on a horizontal floor with a speed of $4\ m/s$. It strikes a uncompressed spring, and compresses it till the block is motionless. The kinetic friction force is $15\ N$ and spring constant is $10,000\ N/m$. The spring compresses by ............. $\mathrm{cm}$

The spring extends by $x$ on loading, then energy stored by the spring is :(if $T$ is the tension in spring and $k$ is spring constant)

A spring of spring constant $ 5 \times 10^3$ $ N/m$  is stretched initially by $5\,cm$ from the unstretched position. Then the work required to stretch it further by another $5\,cm$ is .............. $\mathrm{N-m}$

$A$ $1.0\, kg$ block collides with a horizontal weightless spring of force constant $2.75 Nm^{-1}$ as shown in figure. The block compresses the spring $4.0\, m$ from the rest position. If the coefficient of kinetic friction between the block and horizontal surface is $0.25$, the speed of the block at the instant of collision is ................. $\mathrm{m}/ \mathrm{s}^{-1}$

A block of mass $'m'$ is released from rest at point $A$. The compression in spring, when the speed of block is maximum

Two blocks $A$ and $B$ of mass $m$ and $2\, m$ respectively are connected by a massless spring of force constant $k$. They are placed on a smooth horizontal plane. Spring is stretched by an amount $x$ and then released. The relative velocity of the blocks when the spring comes to its natural length is :-