Question

a stack of books push down on a shelf with 50 n of force. how much force does the shelf push back with? 0 n because it doesnt apply a force to the book 50 n because for every action, there is an opposite and equal reaction need more information 100 n because the shelf is holding the books

Explanation:

According to Newton's third law of motion, for every action, there is an equal and opposite reaction. When the stack of books exerts a force of 50 N on the shelf (action), the shelf exerts an equal (50 N) and opposite (in direction) force back on the books (reaction).

Answer:

50 N because for every action, there is an opposite and equal reaction.