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

What is a perfectly elastic body and a perfectly plastic body?

$A$ rod of length $2 \ m$ rests on a smooth horizontal floor. If the rod is heated from $0^\circ C$ to $20^\circ C$,find the longitudinal strain developed? $(\alpha = 5 \times 10^{-5} / ^\circ C)$

$A$ wire of length $l$ and cross-sectional area $A$ is stretched by a weight $Mg$ such that its length becomes double. What is the stress in the wire?

$A$ cable that can support a load $W$ is cut into two equal parts. The maximum load that can be supported by either part is

Two wires as shown in the figure below, made of steel, have a breaking stress of $12 \times 10^8 \text{ N/m}^2$. The area of cross-section of the upper wire is $0.008 \text{ cm}^2$ and that of the lower wire is $0.004 \text{ cm}^2$. The maximum mass that can be added to the pan without breaking any wire is . . . . . . kg. (Take $g = 10 \text{ m/s}^2$)