Final answer:
The static friction force on the box is equal to the horizontal force applied by the child, which is 65 N, assuming no other horizontal forces are acting on the box and that the static friction can compensate for this force.
Step-by-step explanation:
The question is asking about the static friction force on a box inside a wagon being pulled by a child. Since the box is not moving relative to the wagon, the static friction force must be equal and opposite to the net force acting on the box. The child pulls the wagon with a force of 65 N, but since the question does not mention any other forces such as friction between the wagon and the ground, we'll assume the only horizontal force acting on the box is due to the pull on the wagon.
Considering Newton's first law, since the box does not move relative to the wagon, the static friction force must balance the net horizontal force on the box. Therefore, the static friction force on the box is 65 N, which is the same as the pull force applied by the child. This assumes that the maximum static friction force is at least 65 N, which must be true in this case since the box remains stationary with respect to the wagon.