Consider a book lying on a table. The weight of the book and the normal force by the table on the book are equal in magnitude and opposite in direction. Is this an example of Newton’s third law?

Question

Philoid · Accepted Answer

According to the Newton’s third law, ‘if a body A exerts a force on body B, then B exerts force on an equal in magnitude and opposite in direction’. So, the normal by the table on the book is action but weight of the book is due the force of earth on the book, not due to the table. Thus, it’s not an action reaction pair. Hence, it is not an example of third law of Newton.