Final answer:
The net force (Fnet) acting on box 1 is 5 N, obtained by subtracting the friction force from the thrust force.
Step-by-step explanation:
To solve for the net force (Fnet) acting on box 1, we can use Newton's second law of motion, which is given by the formula Fnet = ma, where m is mass and a is acceleration. In the provided problem, we are given the thrust force and opposing friction force, as well as mass and a specified acceleration of 0 m/s2. Because there's no acceleration, it implies that the net force is zero, due to forces being in equilibrium. Given a thrust of 7 N and opposing friction of 2 N, we find that Fnet = Thrust - Friction
= 7 N - 2 N = 5 N.