The crew of US submarines work on an 18-hour cycle rather than a 24-hour day. They divide into three ‘watches’, each working for 6 hours, with a meal break for the half hour immediately before and another for the half hour immediately after work. The watches change at 05:30, 11:30, 17:30 and 23:30 Universal Time, no matter where in the world they are. How much time for meal breaks does a member of the crew get in a 72-hour (3-day) period?

Group of answer choices

4 hours

4 1/2 hours

3 hours

It depends when the period starts

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)