Answer:
The net force is 392N, pointing down.
Explanation:
The net force is the sum of all forces acting on the rock, namely the gravity ("+" acting downward) and the friction force due to air resistance ("-" acting upward):
[tex]F_{net} = F_g - F_{air}\\F_{net} = m\cdot g - F_{air} = 50kg\cdot 9.8\frac{m}{s^2}-98N= (490-98)N=392N[/tex]
The net force is 392N and pointing down (positive)/
