Dynamics and statistics physics problem

Question

Three books rest horizontally on a table as pictured below. What forces does the middle book exert on each of the other two? Be specific in expressing your answers. 

Link to image: https://docs.google.com/document/d/1oQXf5SVUqD-LB8cIoiS6gdKJxyzL0CTXIEgYKsgzraU/edit?usp=sharing

Answer 1

There are two types of forces in Physics. One is Contact force and the other is non-contact force. The type of for the book in the middle is contact force, and that is how they are upright.