Answer:
Fn = 50 N
Step-by-step explanation:
Net Force
The net force is the sum of all the forces acting on an object.
When all the forces act in a single line, the direction of the forces is given by their signs. Positive signs are assumed to be up and left on both axes.
The box being raised by a force has a weight of W=-125 N. The negative sign indicates the weight points down. The accelerating force goes up and its value is F=175 N. The positive sign indicates this force pushes the box up.
The forces acting on the box are:
The weight W=-125 N
The accelerating force F=175 N
The net force is
Fn = W + F = -125N + 175 N
Fn = 50 N