FYKOS Year 32 Series 6 Problem 2 — bookworm · FYKOS 32 #32.6.2
Physics · mechanics
Problem
Vítek has been spending some time in the library. Because of his clumsiness, a book fell down from a shelf and he managed to press it with a swift move towards the wall. He pushes the book with a force F applied at an angle α (see figure). The book's mass equals M and the coefficient of friction between the wall and the book is μ. Find the condition under which the force keeps the book from falling down (and at rest) and determine the critical value α0, below which there does not exist any force that will keep the book up.