4-14 A mass of 1.5 kg of air at 120 kPa and 24°C is contained in a gas-tight, frictionless piston-cylinder device. The air is now compressed to a final pressure of 600 kPa. During the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. Calculate the work input during this process.

5-48 An adiabatic air compressor compresses 10 L/s of air at 120 kPa and 20°C to 1000 kPa and 300°C. Determine (a) the work required by the compressor, in kJ/kg, and (b) the power required to drive the air compressor, in kW. 1 MPa 300°C Compressor ↑ 120 kPa 20°C 10 L/s FIGURE P5-48 $

4-69E A piston-cylinder device contains 25 ft of nitro- gen at 40 psia and 700°F. Nitrogen is now allowed to cool at constant pressure until the temperature drops to 200°F. Using specific heats at the average temperature, determine the amount of heat loss.

5-62 Refrigerant-134a is throttled from the saturated liquid state at 700 kPa to a pressure of 160 kPa. Determine the tem- perature drop during this process and the final specific vol- ume of the refrigerant. Answers: 42.3°C, 0.0345 m³/kg P₁ = 700 kPa sat. liquid R-134a P₂ = 160 kPa FIGURE P5-62