6.Two wires of the same material and length are stretched by the same force. Their masses are in the ratio 3 : 2. Their elongations are in the ratio

7.If the work done in stretching a wire by 1 mm is 2 J, the work necessary for stretching another wire of same material but with double radius of cross-section and half the length by 1 mm is

8.Two identical wires are suspended from the same rigid support but one is of copper and the other is of iron. Young s modulus of iron is thrice that of copper. The weights to be added on copper and iron wires so that the ends are on the same level must be in the ratio of

9.A uniform wire, fixed at its upper end, hangs vertically and supports a weight at its lower end. If its radius is r, its length L and Young s modulus for the material of the wire is E, the extension is (1) directly proportional to E(2) inversely proportional to r.(3) directly proportional to L

10.A force F is required to break a wire or length l and radius r. What force is required to break a wire, of the same material, having twice the length and six times the radius ?