The pointer reading versus load graph for a spring balance is as given in the figure. The spring constant is ........ $kg/cm$.

For the tangential stress on the cross-section $PQRS$ to be maximum,$\theta = $ ....... $^o$

$A$ metal block of mass $m$ is suspended from a rigid support through a metal wire of diameter $14\,mm$. The tensile stress developed in the wire under equilibrium state is $7 \times 10^5\,N m^{-2}$. The value of mass $m$ is $......kg$.
(Take,$g = 9.8\,m s^{-2}$ and $\pi = \frac{22}{7}$)

The increase in length is $l$ of a wire of length $L$ by the longitudinal stress. Then the stress is proportional to

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 $\,cm$)

The reason for the change in shape of a regular body is