The substances having a very short plastic region are

$Assertion:$ Stress is the internal restoring force per unit area of a body.
$Reason:$ Rubber is more elastic than steel.

If the side of a cube decreases by $1\%$,the volume strain is ........ $\%$.

Wires $W_{1}$ and $W_{2}$ are made of the same material having a breaking stress of $1.25 \times 10^{9} \, N/m^{2}$. $W_{1}$ and $W_{2}$ have cross-sectional areas of $8 \times 10^{-7} \, m^{2}$ and $4 \times 10^{-7} \, m^{2}$,respectively. Masses of $20 \, kg$ and $10 \, kg$ hang from them as shown in the figure. The maximum mass $m$ that can be placed in the pan without breaking the wires is $..... \, kg$. (Use $g = 10 \, m/s^{2}$)

When a load of $80 \,N$ is suspended from a string,its length is $101 \,mm$. If a load of $100 \,N$ is suspended,its length is $102 \,mm$. If a load of $160 \,N$ is suspended from it,then the length of the string is (Assume the area of cross-section is unchanged). (in $\,cm$)

Stress to strain ratio is equivalent to