A uniform steel rod of diameter 20 mm is connected to an aluminium rod of diameter 60 mm at one end. The aluminium rod tapers to a diameter of 20 mm at the other end. The steel rod is 0.6 m long and...

A uniform steel rod of diameter 20 mm is connected to an aluminium rod of diameter 60 mm at one end. The aluminium rod tapers to a diameter of 20 mm at the other end. The steel rod is 0.6 m long and is connected rigidly to the 60 mm Q end of the aluminium rod which is 0.4 m long. If E = 200 GPa for steel and 70 GPa for aluminium, find the total extension of the rod under an axial tensile load of 30 kN.