Your answer brings up important concepts, but let's clarify the reasoning according to Newton's First Law of Motion.
Newton's First Law states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and in the same direction unless acted upon by a net external force. In the case of a book sliding on a table, it initially moves due to the force you applied to it. However, several external forces act upon it that eventually cause it to come to a stop:
-
Friction: This is the primary force acting on the book. When the book slides on the table, friction between the book and the surface of the table opposes its motion. This frictional force gradually slows the book down until it comes to a stop.
-
Gravity: While gravity is indeed acting on the book, it primarily affects the book's weight and keeps it pressed against the table. In this scenario, gravity is not directly responsible for stopping the book's motion but rather contributes to the normal force that affects the frictional force.
-
Inertia: Inertia is a property of matter that describes its resistance to changes in motion. The book has inertia that keeps it moving, but because of the frictional force acting against it, the book cannot maintain its motion indefinitely, and it eventually comes to a stop.
So to summarize, the book stops primarily due to the force of friction acting against its motion, which is consistent with Newton's First Law. Gravity plays a supporting role by affecting the normal force, but it is not the main reason the book stops sliding.