function[E,I,rho,c,L,A]=geometry_materials()
%
icross=input(' Enter the cross-section: \n 1=rectangle  2=solid cylinder  3=other ');
disp(' ');
if(icross==1)
            width=input(' Enter the width (inch) ');
            thick=input(' Enter the thickness (inch) ');
            A=width*thick;
            I=(1./12.)*width*(thick^3.);
end
if(icross==2)
            diam=input(' Enter the diameter (inch) ');
            A=(pi/4.)*(diam^2.);
            I=(pi/64.)*(diam^4.);
end
if(icross ~=1 & icross ~=2)
            disp(' ');
            I = input(' Enter the area moment of inertia (in^4) ');
            %
            disp(' ');
            A = input(' Enter the cross-section area (in^2) ');
end
%
disp(' ');
imat=input(' Enter material: \n 1=aluminum  2=steel  3=other ');
%
if(imat==1)
    rho=0.1;
    E=1.0e+07;
end
if(imat==2)
    rho=0.29;
    E=3.0e+007;
end
if(imat ~=1 & imat ~=2)
    disp(' ');   
    E = input(' Enter the elastic modulus (lbf/in^2) ');
    disp(' ');
    rho = input(' Enter the mass density (lbm/in^3) ');           
 end
%
rho=rho/386.;
%
c=sqrt(E/rho);
%
disp(' ');
L = input(' Enter the length (inch) ');