Answer:
Thermal energy
Explanation:
The book is pushed which then slides over a table and eventually comes to stop. From Newton's first law of motion, we understand that a body comes to rest or is set into motion when an external unbalanced force acts. Here initially the book was pushed which set it into motion but the book come to stop. This means frictional force acted in the opposite direction which stopped it. The kinetic energy transformed into thermal energy (heat).
