Problem11
Section 15.2: The First Law of Thermodynamics and Some Simple Processes (Test prep for AP® courses)

Question

In Figure 15.44, which of the following cycles has the greatest net work output? (a) ABDA
(b) BCDB
(c) (a) and (b) are equal
(d) ADCBA

Figure 15.44
Question by OpenStax is licensed under CC BY 4.0

Final Answer

(d)

Solution video

0:49
Watch this solution with a 7-day free trial
Full access to every solution — cancel anytime · Already a subscriber? Log in
Start free trial →
No ratings yet.

Video Transcript

This is College Physics Answers with Shaun Dychko. The greatest net work output occurs for the process that has the greatest in area enclosed by its loop. So if we consider the process ABDA, the area enclosed is this yellow triangle. For the process BCDB, the total area enclosed is this much. But if you include ADCBA, then this process would include the entire area in purple. And so, for that reason, it is the process with the greatest net work output. So the answer is D.

Comments

toddhibbitts·
Question: Doesn't the direction matter? ABDA and BCDB are both clockwise processes (positive work); whereas, ADCBA is counter-clockwise (negative work). Or am I in error with my thinking?
Like