Here's why:
* Normal Force: This is a contact force that acts perpendicular to the surface of contact. In this case, the table's surface pushes upwards on the book, counteracting the force of gravity pulling the book downwards.
* Gravity: The Earth's gravitational force pulls the book downwards.
* Equilibrium: Because the book is at rest, these two forces (normal force and gravity) are equal and opposite, resulting in a net force of zero. This is why the book remains stationary.
In summary: The table exerts an upward normal force on the book, which is equal in magnitude and opposite in direction to the downward force of gravity, keeping the book at rest.
