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 .............. $\mathrm{N-m}$

Initially spring is in natural length and both blocks are in rest condition. Then determine Maximum extension is spring. $k=20 N / M$

The potential energy of a weight less spring compressed by a distance $ a $ is proportional to

A spring block system is placed on a rough horizontal floor. The block is pulled towards right to give spring some elongation and released.

Write the dimensional formula of $\frac {k}{m}$.

Two identical blocks $A$ and $B$, each of mass $'m'$  resting on smooth floor are connected by a light spring of natural length $L$ and spring constant $K$, with the spring at its natural length. $A$ third identical block $'C'$ (mass $m$) moving with a speed $v$ along the line joining $A$ and $B$ collides with $A$. the maximum compression in the spring is