In an ideal Otto cycle, air is compressed from 1.15 kg/m³ and 2.2 L to 0.26 L, and the net work output of the cycle is 620 kJ/kg. The mean effective pressure (MEP) for this cycle is A)713 kPa B)807 kPa C)638 kPa D)96 kPa E)367 kPa

Question

Quizplus · Accepted Answer

Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 
rho1=1.15 "kg/m^3"
k=1.4
V1=2.2
V2=0.26
m=rho1*V1/1000 "kg"
w_net=620 "kJ/kg"
Wtotal=m*w_net
MEP=Wtotal/((V1-V2)/1000)
 
"Some Wrong Solutions with Common Mistakes:"
W1_MEP = w_net/((V1-V2)/1000) "Disregarding mass"
W2_MEP = Wtotal/(V1/1000) "Using V1 instead of V1-V2"
W3_MEP = (rho1*V2/1000)*w_net/((V1-V2)/1000); "Finding mass using V2 instead of V1"
W4_MEP = Wtotal/((V1+V2)/1000) "Adding V1 and V2 instead of subtracting"

In an Ideal Otto Cycle, Air Is Compressed from 1