(i) Sketch:

(ii) Acceleration:

Horizontal acceleration:

x = 0.2t³

At t = 3.0, a_x = 3.6

Vertical acceleration:

y = 20t − 2t²

At t = 3.0, a_y = -4

Now

and

So the car's acceleration has magnitude 5.38 ms^-2, and direction 312° from the positive x-axis.