A few of the challenging problems below are not much different from the ETS Physics GRE sample tests. In fact, I would imagine that one could create numerous realistic Physics GRE style questions by combining a couple problems below into a single question. For example a "find the force on an inclined plane problem" could be combined with a "friction problem" and viola you might have a physics GRE problem.
Physics Olympiad screening problems (multiple choice) - There is an international physics Olympics for exceptional "secondary school" students. The US team has created a number of sample multiple choice physics questions to help "screen" the US competitors. As a whole they are easier than the practice problems published by ETS but many of the problems are very similar in content and difficulty to the ETS problems. These are quality problems, cover the fundamentals, and can help you to "screen" your own understanding of basic physics principles and I highly recommend them. Problems like these are a great way to work on your problem solving speed, accuracy, and endurance.
New York Regents Physics Exams (physics test) - Here is another collection of quality, yet basic problems similar in difficulty level to the Olympiad ones above. It is true that they were developed as high school physics tests but, fortunately for our purposes, there has been a lot of controversy about the exams being too difficult for high school students.
AP Physics Exams - The two links above could probably satisfy your need for basic multiple choice sample physics problems that cover the fundamentals. However, you might enjoy churning through these types of high school physics tests a rapid rate to efficiently hone your skills so they are firmly ingrained in your mind. If this is the case than you might consider trying out some sample AP physics exam questions. You can find some sample AP Physics problems by visiting the college board physics page and then navigating to find a massive "pdf" file download that has everything you wanted to know about the AP physics exam as well as 40 sample AP physics questions. Unfortunately, I could not find very many free AP physics exam questions available on the web, but numerous books are available for purchase in the test preparation section of most bookstores. Below are some links to AP Physics books on the market. I personally have not gone through all the books, but I am usually impressed by Princeton Review and Kaplan.
- [isbn=0375762272]Cracking the AP Physics B & C Exams, 2002-2003[/isbn] - Princeton Review
- [isbn=0743225902]AP Physics B: An Apex Learning Guide[/isbn] - Kaplan
- How to Prepare for the AP Physics C (isbn=0764118021) - Barron's
- [isbn=076890983X]Peterson's Ap Success: Physics B/C (Ap Success: Physics B/C, 3rd Ed)[/isbn] - Peterson's