2.70 Figure P2.70 shows a gas contained in a vertical piston- cylinder assembly. A vertical shaft...

 

 

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2.70 Figure P2.70 shows a gas contained in a vertical piston- cylinder assembly. A vertical shaft whose cross-sectional area is 0.8 cm is attached to the top of the piston. The total mass of the piston and shaft is 25 kg. While the gas is slowly heated, the internal energy of the gas increases by 0.1 kJ, the potential energy of the piston-shaft combination increases by 0.2 kJ, and a force of 1334 N is exerted on the shaft as shown in the figure. The piston and cylinder are poor conductors, and friction between them is negligible. The local atmospherie pressure is 1 bar and g = 9.81 m/s. Determine, (a) the work done by the shaft, (b) the work done in displacing the atmosphere, and (c) the heat transfer to the gas, all in kJ. (d) Using calculated and given data, develop a detailed accounting of the heat transfer of energy to the gas. F = 1334 N -A = 0.8 cm2 Patm =1 bar -D = 10 cm Gas Fig. P2.70 2.70 Figure P2.70 shows a gas contained in a vertical piston- cylinder assembly. A vertical shaft whose cross-sectional area is 0.8 cm is attached to the top of the piston. The total mass of the piston and shaft is 25 kg. While the gas is slowly heated, the internal energy of the gas increases by 0.1 kJ, the potential energy of the piston-shaft combination increases by 0.2 kJ, and a force of 1334 N is exerted on the shaft as shown in the figure. The piston and cylinder are poor conductors, and friction between them is negligible. The local atmospherie pressure is 1 bar and g = 9.81 m/s. Determine, (a) the work done by the shaft, (b) the work done in displacing the atmosphere, and (c) the heat transfer to the gas, all in kJ. (d) Using calculated and given data, develop a detailed accounting of the heat transfer of energy to the gas. F = 1334 N -A = 0.8 cm2 Patm =1 bar -D = 10 cm Gas Fig. P2.70