First, let's look at the forces acting on the stack of books. The main forces are gravity and normal force. Gravity is the force that pulls objects towards the center of the earth, while the normal force is the force that prevents objects from falling through a surface. In this case, the table is providing the normal force to the stack of books.
Now, let's look at the individual forces on the books. The upper book has the force of gravity pulling it down towards the lower book, while the lower book has the force of gravity pulling it towards the table. The upper book also has the normal force from the lower book pushing it upwards, while the lower book has the normal force from the table pushing it upwards.
Since the mass of the upper book is greater than the lower book, the force of gravity on the upper book will be greater than that on the lower book. However, the normal forces on both books will be equal in magnitude, as they are being pushed upwards by the same surface.
I understand that this may be confusing at first, but with practice and further study, you will get a better understanding of these concepts. Don't hesitate to ask your teacher or classmates for help if you are still struggling. Keep at it, and you will get the hang of it!
