A1.0 kg book is at rest on a table top diagram the forces acting on the book

In the diagram attached, we will be able to see that the total force acting on the book is zero, according to the First Newton law, which states that an object is in equilibrium is the total force exerted on it is zero:

    (1)

Which is the same as:

    (2)

Where   is the weight of the book, which is the product of the mass of the book and the gravity acceleration :

    (3)

Being   and  , the weight of the book is:

    (4)

Then, equation (2) means that the force due to the weight acting on the book is the same in magnitude but in opposite direction to the force the table exerts on the book, which is in accordance with the third Newton law of action and reaction.