$1.$

A car speeding steady at $10$ m$/$s from A due south for $20$ minutes and then at $12$ m$/$s due west for $10$ minutes to B$.$ Find :

a$)$ the displacement between A and B; and$($s $=13994$ m; S$30\mathrm{.}96$oW$)$

b$)$ the average velocity between A and B$.($v $=7\mathrm{.}77$ m$/$s$)$