Answer
See the figures below.
Work Step by Step
a) The object is speeding up in the direction of the south of the west. This means that the net acceleration is pointing in the same direction of velocity which is south of the west. Hence, the net force is also in the same direction.
b) The object is slowing down in the direction of the north of the east. This means that the net acceleration is pointing in the same direction of velocity which is north of the east. Hence, the net force is also in the same direction.
