The radiator of a steam heating system has a volume of 16 l and is filled with superheated water vapor at 200 kpa and 150°c. at this moment, both the inlet and the exit valves to the radiator are closed. after a while the temperature of the steam drops to 40°c as a result of heat transfer to the room air. determine the entropy change of the steam during this process.

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2