11.A cube of aluminium of sides 0.1 m is subjected to a shearing force of 100 N. The top face of the cube is displaced through 0.02 cm with respect to the bottom face. The shearing strain would be

12.The length of an elastic string is a metre when the tension is 4 N, and b metre when the tension is 5 N. The length in metre when the tension is 9 N is

13.A 2 m long rod of radius 1 cm which is fixed from one end is given a twist of 0.8 radius. The shear strain developed will be

14.A helical spring extends 40 mm when stretched by a force of 10 N, and for tensions up to this value the extension is proportional to the stretching force. Two such springs are joined end to-end and the double-length spring is stretched 40 mm beyond its natural length. The total strain energy, in J, stored in the double spring is

15.Two wires of the same material and length but diameters in the ratio 1 : 2 are stretched by the same force. The potential energy per unit volume for the two wires when stretched will be in the ratio