Forces Acting on the Book:

1. Gravity (Weight): This is the force pulling the book straight down towards the center of the Earth. It's represented by mg, where 'm' is the book's mass and 'g' is the acceleration due to gravity (approximately 9.8 m/s²).

2. Normal Force: This is the force exerted by the slope on the book, perpendicular to the surface of the slope. It prevents the book from falling through the slope.

3. Friction: This force opposes the book's motion down the slope. It acts parallel to the surface and can be static (preventing motion) or kinetic (opposing motion while the book is sliding).

Breaking Down the Forces:

* Weight (mg): We can break this force into two components:

* Force parallel to the slope (mg sin θ): This component is what causes the book to slide down the slope.

* Force perpendicular to the slope (mg cos θ): This component is balanced by the normal force.

* θ is the angle of the slope.

* Normal Force: It's equal in magnitude and opposite in direction to the component of weight perpendicular to the slope (mg cos θ).

* Friction:

* Static Friction: This force prevents the book from moving until the force parallel to the slope (mg sin θ) exceeds the maximum static friction force.

* Kinetic Friction: This force opposes the book's motion once it starts sliding. It's proportional to the normal force and the coefficient of kinetic friction (μk).

In Summary:

The forces acting on a book on a slope are:

* Weight (mg)

* Normal Force

* Friction (static or kinetic)

The book's motion depends on the balance of these forces. If the force pulling it down the slope (mg sin θ) is greater than the maximum static friction force, the book will start sliding.