The discussion revolves around calculating the work done by a heat engine operating on a specific cycle, with a focus on interpreting a pressure-volume graph. The original poster presents an initial calculation based on given parameters, including maximum pressure.
Participants are actively exploring different interpretations of the graph and the calculations involved. Some have suggested conversion methods for pressure, while others are questioning the assumptions about the direction of work and the implications of negative values.
There is a noted confusion regarding unit conversions and the interpretation of the graph, particularly concerning the height used in the area calculation. The original poster has expressed frustration over incorrect submissions, indicating a need for clarity on the calculations.
jagged06 said:Work will be the area of the box the system creates.
You can approximate the area just by looking at the graph, and using formula for area of a parallelogram, which this appears to be.
huybinhs said:Yes, I looked on the graph:
Base = 6 , h= 2 so Area = 6*2 = 12, correct?
huybinhs said:Ok, so 6 * 0.01 = 0.06 then * 1013.25 = 60.795 = answer correct?
just submited it and INCORRECT :(
jagged06 said:My suggestion is to convert .01 atm to Pa FIRST.
as in .01 atm = 1013.25 Pa <-- that is now your height
there is no need to convert the Volume so
W = 1013.25 * 6
Answer will be in Joules
OH THE CONVERSIONS!
jagged06 said:Because of the flow of the engine.
Let's take it in sections:
starting at the top left corner, the system moves down and to the right, and everything below this part of the graph would be positive. Delta V in this case would be positive.
Once it goes back up and back to the left Delta V in this case, would be negative, and the area below it is larger.
Direction matters here, I'm just not finding a good example. I wish I had one.