If you create two courses -- courseA and courseB --
You can assign professorX as the contact person for each course.
You get to choose an initial password for professorX when you create the course.
so professorX will have login professorX in courseA and his initial password will be passwordA.
For the second course professorX will have login professorX in courseB and his initial password will be passwordB. (You can make passwordB the same as passwordA or not as you choose.)
As far as courseA and courseB are concerned professorX is a different person in each course. The two courses have separate user login tables.
In the admin course we record the contact person for each new course -- mostly just to serve as a reminder -- we never use the admin course as a real webwork course (i.e. we never assign problems in that course ). In the admin course
we will have login entries such as to professorX_courseA and professorX_courseB so this reminds the site administrator who is the contact person for each course.
ProfessorX will never login to the admin course and doesn't need to know their real password.