<Homework 6>1. A thick aluminum rod and a thin steel wire are attached in parallel, as shownin the figure. The temperature is 20°C. Both the rod and the wire are 85 cmlong and neither is under stress. The system is heated to 150°C. Calculate theresulting stress in the wire, assuming that the rod expands freely.2. A composite bar of length L = L1+ L2is made from a bar of material 1 andlength L1, attached to a bar of material 2 and length L2. Show that the effectivecoefficient of linear expansionfor this is given by= (ααα1L1+ α2L2)/L.3. A sample of gas expands from 1.0 to 4.0 m3while its pressure decreases from40 to 10 Pa. How much work is done by the gas if its pressure with volumeaccording to each of the three processes shown in th p-V diagram as below?4. Consider 100J of work are done on a system and 70 cal of heat are extractedfrom the system. In the sense of the first law of thermodynamics, what are thevalues (including algebraic signs) of W, Q and internal energy respectively?