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Solution to Exercise 6.6

12 October, 2015 - 11:45
    clc                             % Clear screen
disp('This script computes the work done by')
disp('The gas in expanding from volume v1 to v2')
disp(' ')                    % Display blank line
a=input('Enter the constant a: ');
b=input('Enter the constant b: ');
p_i=input('Enter the initial pressure [kPa]: ');
v_i=input('Enter the initial volume [m3]: ');
v_f=input('Enter the final volume [m3]: ');
k=(p_i+(a/(v_i^2))*(v_i-b));    % Calculating constant k
v=v_i:.001:v_f;                 % Creating a row vector for volume
p=(k./(v-b))-(a./(v.^2));       % Computing pressure for volume
WorkDone=trapz(v,p);            % Integrating p*dv
disp(' ')                       % Display blank line
str = ['The work done by the gas in expanding from ', num2str(v_i),...
' m3 to ' num2str(v_f), ' m3 is ', num2str(WorkDone), ' kW.'];
disp(str);

The output is:

    This script computes the work done by
The gas in expanding from volume v1 to v2
Enter the constant a: .01
Enter the constant b: .001
Enter the initial pressure [kPa]: 100
Enter the initial volume [m3]: 1
Enter the final volume [m3]: 2

The work done by the gas in expanding from 1 m3 to 2 m3 is 69.3667 kW.