Recent content by Ravey

1. A medieval city has the shape of a square and is protected by walls with length 550 m and height 16 m. You are the commander of an attacking army and the closest you can get to the wall is 100 m. Your plan is to set fire to the city by catapulting heated rocks over the wall (with an initial...

Got it! Qh=Q_c+W_out = 280J + 40J = 320J. 40/320 = efficiency.

Stumped too I see ;)

Thanks! I believe that is heat leaving the engine*, but what do I do? Add them? According to some note Qc is the sum of the heat leaving the engine. So I assume so. However, qh is not 280-40 = 240. What's going wrong?

1. What is the thermal efficiency for the heat engine shown in the figure? What is the heat extracted from the hot reservoir for the heat engine shown in the figure?t Figure shown here: 2.Wout = 1/2 B*H Also, Qc=Qh-Wout, efficiency: Wout/Qh 3. Wout = .5 * 200KPA*...