$($iv$)$ Assuming $A_1=800m{m}^2,A_2=40m{m}^2,L_1=1\mathrm{.}2m,L_2=0\mathrm{.}7m,=30,$ and all

members have elastic modulus $E=200$GPa, plot the force$-$deformation response, i$.$e$.,$

a plot of $P($on the $y-$axis$)$ against $D_B($on the $x-$axis, ranging from $0$ to $1\mathrm{.}3m).$ You

will find it helpful to first create an array of possible values of $,$ and then use the

expressions from Parts $($i$)$ and $($iii$)$ to relate them to $O_B$ and $P$ respectively. Explain

the shape of the force$-$deformation curve you have obtained in terms of the physical

behaviour of the truss under large deformations.