The Andes Physics Tutor
Teachers just click "Try Andes" and select the topics and problems and then assign them to the students. The students enter their name (no login) and then complete the problem. The problem screen is nice with a variety of tools for the students to use.
There are over 500 problems that cover most of the topics that a first year, 2 semester, Trig/Algebra based physics course would cover. Andes can be used for high school physics or 1st year college physics.
This is a great, free resources for physics teachers and physics students.
Currently, the Andes project lives at Arizona State University with support from the Pittsburgh Science of Learning Center, National Science Foundation award No. SBE-0836012. Previously, Andes was developed at the University of Pittsburgh and the United States Naval Academy with support from the Office of Naval Research, grant No. N00014-96-1-0260.