Vectors in Kinematics

[upper topaz]

Please help with part b

[acoustic shoal]

It will be due east of A when the particle has the same y-coord as A

if you take
A as (0,0)
and find the point B using
s=ut+0.5at^2, t=3
say the y coord is y
thats y units above A
and at B the motion after is at constant velocity, and it moves downwards at 2m/s
so
2*t = y

so at t = y/2
the particles position is purely horizontal relative to A

[outer owl]

Is the answer for part b 6 seconds