Oxygen enters an insulated 12-cm-diameter pipe with a velocity of 90 m/s. At the pipe entrance, the oxygen is at 240 kPa and 20°C; the exit it is at 200 kPa and 18°C. Calculate the rate at which entropy is generated in the pipe. The rate at which entropy is generated in the pipe is:

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.