Questions in Mechanical Properties of Solids

Select	Question
	If a spring extends by $x$ on loading, then the energy stored by the spring is (if $T$ is tension in the spring and $k$ is spring constant)
	On stretching a wire, the elastic energy stored per unit volume is
	When a force is applied on a wire of uniform cross-sectional area $3\times {{10}^{-6}}\,{{m}^{2}}$and length 4m, the increase in length is $1 mm$. Energy stored in it will be $(Y=2\times {{10}^{11}}\,N/{{m}^{2}})$
	K is the force constant of a spring. The work done in increasing its extension from ${{l}_{1}}$ to ${{l}_{2}}$ will be
	When a 4 kg mass is hung vertically on a light spring that obeys Hooke's law, the spring stretches by 2 cms. The work required to be done by an external agent in stretching this spring by 5 cms will be $(g=9.8\,metres/sec^{2})$
	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
	The elastic energy stored in a wire of Young's modulus $Y$ is
	A wire of length 50 cm and cross sectional area of 1 sq. mm is extended by 1 mm. The required work will be $(Y=2\times {{10}^{10}}\,N{{m}^{-2}})$
	The work per unit volume to stretch the length by $1%$ of a wire with cross sectional area of $1\,m{{m}^{2}}$ will be. $[Y=9\times {{10}^{11}}\,N/{{m}^{2}}]$
	When load of 5kg is hung on a wire then extension of 3m takes place, then work done will be