If the tension on a wire is removed at once,then

Two wires of the same material (Young's modulus $Y$) and same length $L$ but radii $R$ and $2R$ respectively are joined end to end and a weight $W$ is suspended from the combination as shown in the figure. The elastic potential energy in the system is

$A$ wire $2 \,m$ in length suspended vertically stretches by $10 \,mm$ when a mass of $10 \,kg$ is attached to the lower end. The elastic potential energy gained by the wire is ...... $J$ (take $g=10 \,m/s^2$)

An elastic material of Young's modulus $Y$ is subjected to a stress $S$. The elastic energy stored per unit volume of the material is

Two steel wires having same length are suspended from a ceiling under the same load. If the ratio of their energy stored per unit volume is $1: 4$,the ratio of their diameters is

One end of a slack wire (Young's modulus $Y$,length $L$ and cross-sectional area $A$) is clamped to a rigid wall and the other end to a block (mass $m$),which rests on a smooth horizontal plane. The block is set in motion with a speed $v$. What is the maximum distance the block will travel after the wire becomes taut?