Based on the model, which statement best explains why point A is experiencing summer?
A. Earth's equator is receiving the least direct rays of sunlight.
B. Earth's southern hemisphere is tilted toward the Sun.
C. Earth's south pole is receiving the most direct rays of sunlight.
D. Earth's northern hemisphere is tilted toward the Sun.

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.