Add ap-physics info to books.txt
Add ap-physics info to books.txt

Connexions/cnx-rulesets,Connexions/cnx-recipes,Connexions/cnx-rulesets,Connexions/cte,Connexions/cnx-recipes,Connexions/cnx-recipes,Connexions/cnx-recipes,Connexions/cnx-rulesets,Connexions/cte,Connexions/cnx-recipes,Connexions/cnx-rulesets