A 12 N falling Object encounters 4N of air resistance. The magnitude of the net force on the object is?
The gravity force of 12N acts downward (towards the Earth). The air resistance force acts upward and counteracts the gravity force. And its magnitude 4N is smaller than the magnitude of the gravity force.
Therefore the net force acts downward and its magnitude is the difference between the magnitudes of the gravity and air resistance forces.
12N-4N=8N. This is the answer.