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// Theory and Problems of Thermodynamics
// Chapter 1
// Basic Concepts
// Example 12
clear ;clc;
//Given data
V1 = 0.1 //initial volume in m^3
P1 = 200 //initial pressure in kPa
Pa = 100 //ambient atmosphere pressure in kPa
V2 = 0.2 //final volume in m^3
P2 = 600 //final pressure in kPa
//Calculate work done by gas
// force balance at any instance gives
// W = integrate('P','V',1,2) where P = Pa + K*(V-V0)/(A^2)
// W = integrate('Pa + K*(V-V0)/(A^2)','V',1,2)
// W = Pa*(V2-V1) + K*((V2-V0)^2 - (V1-V0)^2)/(2*A^2)
// W = Pa*(V2-V1) + K*(V2-V1)*((V2-V0) + (V1-V0))/(2*A^2)
// W = (V2-V1) * (Pa + (P2-Pa+P1-Pa)/2)
W = (V2 - V1)*(P1 + P2)/2 //work done by gas in kJ
// Results
mprintf('Work done by gas = %2.0f kJ', W)
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