Question

1. name the missing force... a) frictional force b) buoyant force c) weight force d) thrust

Explanation:

The man is pushing the box to the left. In the horizontal direction, there must be a frictional force opposing the applied - force $F_A$. The normal force $F_N$ acts vertically upward, the gravitational force $F_g$ acts vertically downward. The missing force in the horizontal direction, opposing the applied force, is the frictional force. Buoyant force acts in a fluid medium and is not relevant here. Weight force is already represented as $F_g$. Thrust is usually associated with propulsion in engines and is not applicable in this context.

Answer:

a) frictional force