Hooke's law is applicable for ....

The breaking stress of aluminium is $7.5 \times 10^7 \,N m^{-2}$. The greatest length of aluminium wire that can hang vertically without breaking is ......... $\times 10^3 \,m$ (Density of aluminium is $2.7 \times 10^3 \,kg m^{-3}$ and $g = 9.8 \,m s^{-2}$)

The length of an elastic string is $a$ metres when the longitudinal tension is $4 \ N$ and $b$ metres when the longitudinal tension is $5 \ N$. The length of the string in metres when the longitudinal tension is $9 \ N$ is

When is the force between atoms attractive? When is it repulsive?

$A$ force of $10 \,N$ is required to break a wire of radius $1 \,mm$. The force required to break the wire of the same material, but radius $3 \,mm$ will be

The elastic behaviour of a material for linear stress and linear strain is shown in the figure. The energy density for a linear strain of $5 \times 10^{-4}$ is $\dots \; kJ/m^3$. Assume that the material is elastic up to the linear strain of $5 \times 10^{-4}$.