A cylindrical $($d$0=30$mm$)$ metal specimen with BCC crystal structure, atomic radius of $0\mathrm{.}115$ nm and atomic weight $90\mathrm{.}5$ g$/$mol$,$ is subjected to a tensile test with a load of $310000$ N$.$ If the deformation is totally elastic and the Young modulus is equal to $160$ GPa, determine the resulting strain and calculate the theoretical density $($g$/$cm$3)$ of the metal.