A brass rod of cross-sectional area $1\,c{m^2}$ and length $0.2\, m$ is compressed lengthwise by a weight of $5\, kg$. If Young's modulus of elasticity of brass is $1 \times {10^{11}}\,N/{m^2}$ and $g = 10\,m/{\sec ^2}$, then increase in the energy of the rod will be
${10^{ - 5}}\,J$
$2.5 \times {10^{ - 5}}\,J$
$5 \times {10^{ - 5}}\,J$
$2.5 \times {10^{ - 4}}$ $J$
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 work done per unit volume to stretch the length of area of cross-section $2 \,mm ^2$ by $2 \%$ will be ....... $MJ / m ^3$ $\left[Y=8 \times 10^{10} \,N / m ^2\right]$
Why do spring balances show wrong readings of weight after they have been used for a long time ?
If $x$ longitudinal strain is produced in a wire of Young's modulus $y,$ then energy stored in the material of the wire per unit volume is
A $2 \,m$ long rod of radius $1 \,cm$ which is fixed from one end is given a twist of $0.8$ radians. The shear strain developed will be