$39.$

Suppose the particles in the preceding problem have masses m$1=0\mathrm{.}10$kg$,$m$2=0\mathrm{.}20$kg$,$m$3=0\mathrm{.}30$kg$,$m$1=0\mathrm{.}10$kg$,$m$2=0\mathrm{.}20$kg$,$m$3=0\mathrm{.}30$kg$,$ m$4=0\mathrm{.}40$kgm$4=0\mathrm{.}40$kg$.$ The velocities of the particles are v$1=2\mathrm{.}0$i$$m$/$sv$1=2\mathrm{.}0$i$^$m$/$s$,$ v$2=(3\mathrm{.}0$i$3\mathrm{.}0$j$)$m$/$sv$2=(3\mathrm{.}0$i$^3\mathrm{.}0$j$^)$m$/$s$,$ v$3=1\mathrm{.}5$j$$m$/$sv$3=1\mathrm{.}5$j$^$m$/$s$,$ v$4=4\mathrm{.}0$i$$m$/$sv$4=4\mathrm{.}0$i$^$m$/$s$.($a$)$ Calculate the angular momentum of each particle about the origin. $($b$)$ What is the total angular momentum of the four$-$particle system about the origin?