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

$A$ lift of mass $1600 \text{ kg}$ is supported by a thick iron wire. If the maximum stress which the wire can withstand is $4 \times 10^8 \text{ N/m}^2$ and its radius is $4 \text{ mm}$, then the maximum acceleration the lift can take is . . . . . . $\text{m/s}^2$. (Take $g = 10 \text{ m/s}^2$ and $\pi = 3.14$)

The value of tension in a long thin metal wire has been changed from $T_{1}$ to $T_{2}$. The lengths of the metal wire at two different values of tension $T_{1}$ and $T_{2}$ are $l_{1}$ and $l_{2}$ respectively. The actual length of the metal wire is:

Two equal and opposite forces are exerted on a bar (rod) as shown in the figure. The plane $PQ$ makes an angle $\theta$ with the cross-section $PR$ (having area $a$). Find the tensile stress on the plane $PQ$.

What is the difference between a rigid body and a solid body?

$A$ and $B$ are two wires. The radius of $A$ is twice that of $B$. They are stretched by the same load. Then the stress on $B$ is