An air-standard dual cycle has a compression ratio of 14 and a cutoff ratio of 1.2. the pressure ratio during the constant-volume heat addition process is 1.5. determine the thermal efficiency, amount of heat added, the maximum gas pressure and temperature when this cycle is operated at 80 kpa and 20°c at the beginning of the compression. use constant specific heats at room temperature.

A2-m rigid tank initially contains saturated water vapor at 100 kpa. the tank is connected to a supply line through a valve. steam is flowing in the supply line at 600 kpa and 300 c. the valve is opened, and steam is allowed to enter the tank until the pressure in the tank reaches the line pressure, at which point the valve is closed. a thermometer placed in the tank indicates that the temperature at the final state is 200°c. determine (a) the mass of steam that has entered the tank (b) the amount of heat transfer.