A rod AD, consisting of three segments AB, BC and CD joined together, is hanging vertically from a fixed support at A. The lengths of the segments are respectively 0.1 m, 0.2 m and 0.15 m. The crosssection of the rod is uniformly equal to 10^{–4} m^{2} . A weight of 10 kg is hung from D. Calculate the displacements of the points B, C and D using the data on Young’s moduli given below (neglect the weight of the rod).

Y_{AB} = 2.5 × 10^{10} N/m^{2} , Y_{BC} = 4.0 × 10^{10} N/m^{2} and Y_{CD} = 1.0 × 10^{10} N/m^{2} .