A wire of length ' $L$ ' and area of cross section ' $A$ ' is made of material of Young's modulus ' $r$. It is stretched by an amount ' $x$ '. The work done in stretching the wire is
A lift is tied with thick iron ropes having mass ' $M$ '. The maximum acceleration of the lift is ' $a$ ' $\mathrm{m} / \mathrm{s}^2$ and maximum safe stress is ' S ' $\mathrm{N} / \mathrm{m}^2$. The minimum diameter of the rope is
1. Two identical wires of substances ' $P$ ' and ' $Q$ ' are subjected to equal stretching force along the length. If the elongation of ' $Q$ ' is more than that of ' $P$ ', then
Work done in stretching a wire through 1 mm is 2 J . What amount of work will be done for elongating another wire of same material, with half the length and double the radius of cross section, by 1 mm ?