$A$ wire of length $L$ and cross-sectional area $A$ is made of a material of Young's modulus $Y$. It is stretched by an amount $x$. The work done is

On stretching a wire,the elastic energy stored per unit volume is

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

$A$ boy's catapult is made of a rubber cord which is $42\, cm$ long,with $6\, mm$ diameter of cross-section and of negligible mass. The boy keeps a stone weighing $0.02\, kg$ on it and stretches the cord by $20\, cm$ by applying a constant force. When released,the stone flies off with a velocity of $20\, m/s$. Neglect the change in the area of cross-section of the cord while stretched. The Young's modulus of rubber is closest to:

$A$ thick rope of density $\rho$ and length $L$ is hung from a rigid support. The Young's modulus of the material of the rope is $Y$. The increase in length of the rope due to its own weight is

The elastic potential energy of a strained body is