a) \displaystyle v=v_0+at=10m/s+3 m/s^2\csot 6s= 28m/s
b) OA:v2=v02+2aÁs=)(10(m=s)2=0+2(4m=s2)ÁOA(m) =)OA=12;5m AB:s=v+21Áat2=)AB=(10m=s)Á(6s)+21(3m=s2)(6s)2=114m
OB=OA+AB=126;5m