How Is Net Energy Transferred in a Cyclic Thermodynamic Process?

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In the cyclic thermodynamic process described, the net energy transferred to the system by heat during one complete cycle needs to be calculated from the heat values (Q) for each segment. The user initially calculates the net heat transfer as 40,000J, but questions its accuracy. The discussion emphasizes the importance of correctly summing the heat values for each segment of the cycle to determine the total heat transfer. Additionally, the impact of reversing the cycle on heat transfer is noted, suggesting that the path ACBA will yield a different net energy transfer. Clarification on the calculations and methodology is sought to ensure accurate results.
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Homework Statement



A gas is taken through the cyclic process described by Figure P12.16.

http://www.webassign.net/sf/p12_16.gif

(a) Find the net energy transferred to the system by heat during one complete cycle.

(b) If the cycle is reversed -- that is, the process follows the path ACBA -- what is the net energy transferred by heat per cycle?

PV=[nR]T
[nR]=PV/T
W=-P(deltaV)What I have done so far:______P(kPa)--------V(m^3)------------U(J)--------------[nR]
A_____2x10^3--------- 6 --------------18x10^3 ----------43.96
B_____8x10^3----------10-------------120x10^3---------293.04
C_____2x10^3---------10---------------30x10^3-----------73.30
_________W(J)___________Q(J)___________deltaU(J)
A->B_____-8,000________110,000_________102,000
B->C______0__________-90,000___________-90,000
C->A_____8,000_________20,000__________-12,000

Wouldn't the net energy transferred to the system by heat be the sum of the Q values? I get 40,000J for this, but it seems to be wrong. Suggestions would be greatly appreciated.thanks
 
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I know its a bit tedious, but any suggestions?
 

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