Question: A book is resting on top of a table. 1. Do the downward force of gravity and the upward force of normal force constitute a 3rd law pair? (Yes/No) 2. The reaction to the force of gravity is exerted on the (earth/table/book) by the (earth/table/book). Its direction is (upward/downward). According to Newton's third law, I know that reaction force occurs when object A receiving an impact from object B exerts a force equal in magnitute but opposite in direction to object B. But how do you show this on free body diagram? Thank you.