Your friend claims to have constructed an engine that operates between two reservoirs at 500 K and 350 K. She says that, in each cycle, the engine extracts 6000 J of heat from the high temperature reservoir, rejects 3900 J of heat to the low temperature reservoir and performs 2100 J of work. Would you invest in this engine

d is the correct answer

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this

answer( sicar );