Answer
(a) Northward.
(b) Northward.
(c) Zero.
(d) Zero.
(e) Downward.
Work Step by Step
(a) The net force and the acceleration have the same direction.
(b) If you are slowing down, acceleration and velocity have opposite directions. That is, the car is accelerating northward. As the net force and the acceleration have the same direction, the force is also pointing to the North.
(c) Constant speed-> $a=0$ -> $F=0$
(d) Constant speed-> $a=0$ -> $F=0$
(e) The net force in this case is the weight (1 force only). To be more precise, we must say that this force points to the center of the Earth, but, for such a short distance, compared to the radius of the Earth, we can say downward.
