A load of 1 kg weight is attached to one of a steel wire of area of cross- section $3\; mm ^2$ and young's modulus $10^{11}\;Nm^2$. The other end is suspended vertically from a book on a wall, then the load is pulled horizontally and released. When the load passes through its lowest position the fractional change in length is $(g= 10 m/sec^2)$