The answers are:

1. Four factors to be considered in order to determine whether a specific action is to be considered “fair use”:

1. The purpose and character of the use, including whether such use is of commercial nature or is for nonprofit educational purposes.
2. The nature of the copyrighted work.
3. The amount and substantiality of the portion used in relation to the copyrighted work as a whole.
4. The effect of the use upon the potential market for or value of the copyrighted work.

2. Yes, you can be sued for copyright even if you do not gain a profit.

3. No, a single copy may be made of any of the following by a teacher for his or her scholarly research or use in teaching or preparation to teach a class: A chapter from a book; an article from a periodical or newspaper; a short story, short essay or short poem, whether or not from a collective work; or a chart, graph, diagram, cartoon or picture from a book, periodical, or newspaper. It is not infringement.

4. The fair use provision of the Copyright Act allows reproduction and other uses of copyrighted works under certain conditions for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship or research. Additional provisions of the law allow uses specifically permitted by congress to further educational and library activities.