The load versus elongation graph for four wires of the same material and same length is shown in the figure. The thinnest wire is represented by the line

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

Consider a long steel bar under a tensile stress due to force $F$ acting at the edges along the length of the bar (as shown in figure). Consider a plane making an angle $\theta$ with the length. What are the tensile and shearing stresses on this plane?
$(a)$ For what angle is the tensile stress a maximum?
$(b)$ For what angle is the shearing stress a maximum?

If a solid breaks under a pressure greater than $13 \ atm$ and that solid has a specific gravity of $4$,what is the maximum height of a cylinder made from the solid that can be built at the Earth's surface (in $m$)? (Note: $1 \ atm = 10^5 \ Pa$ and take $g = 10 \ m/s^2$.)

Let a wire be suspended from the ceiling (rigid support) and stretched by a weight $W$ attached at its free end. The longitudinal stress at any point of cross-sectional area $A$ of the wire is:

Explain with the illustration of cranes the applications of the elastic behaviour of materials.