Answer:
The worker pulls the boxes. The force (F) on box B acts towards right direction. The weigh (mg) of the box acts in the downward direction where as reaction force -Normal force (N) acts in the upward direction.
The contact surface between box and ground is not smooth and hence friction (f ) would act in the opposite direction of the motion of the box. Tension (T) exist in the rope connecting the two boxes.
The free body diagram of box B is attached below showing all the forces acting on it.
