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Question 1 (20 points): a. (10 points) What is the difference between heat transfer and work? b. (10 points) A gas in a piston-cylinder device is compressed, and as a result its temperature rises. Is this a heat or work interaction? Question 2 (40 points): Steam in a piston-cylinder assembly undergoes a polytropic process, with n = 4, from an initial state where p₁ = 3.45 Mpa, v₁ = 0.10 m³/kg, u₁ = 3170 kJ/kg to a final state where u₂ = 2300 kJ/kg. During the process, there is a heat transfer from the steam of magnitude 360 kJ. The mass of steam is 0.4 kg. Negle ting changes in kinetic and potential energy, then determine: a. (15 points) The boundary work. b. (15 points) The final specific volume in m³/kg. c. (10 points) The final pressure. steam Q=360 kJ
Question 3 (40 points): Water is pumped from a lake to a storage tank 15 m above at a rate of 60 L/s while consuming 18 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine a. (20 points) The overall efficiency of the pump-motor unit (consider density of the water b. (20 points) The pressure difference between the inlet and the exit of the pump. 15 m Pump P Storage tank Р = 1000 kg/m³).