1. Aim: How do we explain other physical systems involving friction?

2. Analyze the following:
Turn and Talk: Explain what conditions must be necessary for the book to not fall by identifying the forces acting on the book
The force of gravity pulls down on the book.
The normal force pushes the book to the left.
The force of friction pushes up on the book.
And the force shown pushes into the book

3. Problem 1
If the book has a mass of 2 kg and the coefficient of friction between the wall and book is 0.25, how great a force must the book be pushed with in order to not fall?

5. Analyze the following
A force F pulls a slab to the left. There exists a coefficient of friction between the block and slab. There exists no friction between the slab and table.
a) What is the direction of the friction force on the block due to the slab? To the right
b) What is the direction of the friction force on the slab due to the block? To the left
c) If the slab moves with the block without slipping, what type of friction must exist between the block and slab? Static Friction

6. Problem 2
Assume the block has a mass of 1 kg, the slab has a mass of 5 kg, the coefficient of friction between the block and slab is 0.4. What is the maximum force F that one can pull the block with so that the slab does not slip? a) Draw a freebody diagram for each mass. b) Write ma equations for each mass.

8. Problem 3
Find the maximum force F that can be applied to the 4 kg mass such that the 2 kg mass will move with it.