A tank containing air is stirred by a paddle wheel. The work input to the wheel is 14000 kJ and heat transferred to the surrounding from the tank is 5000 kJ. The change in internal energy of the system (air) is:
1
-9000 kJ
2
+9000 kJ
3
+19000 kJ
4
-19000 kJ
5
+29000 kJ