(a) Chilled water enters a thin-shelled 5-cm-diameter, 150 -m-long pipe at 7C at a rate of 0.98 kg/s and leaves at 8C. The pipe is exposed to ambient air at 30C with a heat transfer coefficient of 10W/m2C. If the pipe is to be insulated with glass wool (k=0.05W/mC) in order to decrease the temperature rise of water to 0.25C, determine the required thickness of the insulation. State your assumptions, if any. [Hint: Cp of water =4180J/kgC. You might take the initial guess of insulation thickness =3cm] (14 marks) (b) Consider two walls, A and B, with the same surface areas and the same temperature drops across their thickness. The ratio of thermal conductivity is kA/kB=4 and the ratio of the wall thickness LA/LB=2. What is the ratio of heat transfer rates through the walls QA/QB ? Choose your answer from the following list and provide a short explanation to your answer. (i) 0.5 , (ii) 1 , (iii) 2 , (iv) 4, , v) 8