Question

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?

Answer 1

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.

• We all know that each and every object tends to remain in equilibrium.
• And Newton's Third Law says that "for every action, there is an equal and opposite reaction".
• So, if an object is experiencing a force in one direction then the same object will also experience a force in the opposite direction although if the object is at rest.
• In our above example, the book is on the table which exerts a force on the table which is it's weight in vertically downwards direction. So, the table will also exert a force on the book in vertically upwards direction which we call the normal force.

So, yes this is an example of Newton's third law.

Answer 2

On Considering 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. So this an example of Newton's third law.

Explanation:

When a book lies on the table, the normal force on the table by the book and the book's weight are equal in magnitude and it has opposite direction. So, this is the example of Newton's third law of motion.  

As per the Newton's third law, each and every action has equal and opposite reaction. The report means that in each and every interface, on the two interacting objects, there is  two(pair)  forces acts on them. The forces have the size on the first item equals the force's size on the second object.