Introductory Static Friction on an Incline Problem

The video tutorial explains how to determine the coefficient of static friction between a book and an inclined plane. It begins with identifying known values and proceeds to draw a free body diagram to illustrate the forces involved. The tutorial then sums the forces in both parallel and perpendicular directions to the incline. Finally, it derives the coefficient of static friction using trigonometric relationships, concluding with a calculation based on a 15-degree incline angle.

What is the relationship between the force of gravity parallel and the force of static friction before the book starts to move?

What is the formula for the maximum force of static friction in this context?

How do you calculate the coefficient of static friction using the incline angle?