$(25$pts$)$ Section $AB$ is Titanium alloy Ti$-6$Al$-4$ V and has a cross$-$sectional area of $0\mathrm{.}10i{n}^2.$ Section BC is Bronze C$86100$ alloy and has a cross$-$sectional area of $0\mathrm{.}12$in ${?}^2.$ Section CD is Stainless $304$ alloy steel and has a cross$-$sectional area of $0\mathrm{.}08i{n}^2.$

a$.$ Find the internal force on each section and indicate whether it is in compression or tension.

b$.$ Find the change in length of each section in inch.

c$.$ Find the total change in length.