A Box Is Pushed Across a Horizontal Table by a Boy

Multiple Choice

A box is pushed across a horizontal table by a boy applying a force of 32 N to the box. A force of friction of magnitude 19 N acts opposite the direction of motion. A stiff wind also opposes the box's motion. What force does the box exert on the boy's hand?

A) 13 N
B) 32 N
C) 51 N
D) Without knowing the force the wind applies, the question cannot be answered.