I'm of the opinion that homework should count for ~50%+ of the total grade for physics classes (at least beyond the introduction ones). The kind of physics questions which are really worth asking take hours to solve, and often times have additional parts like writing computer programs. This is simply not something you can replicate in a 1.5hr exam period.
For the same reason, I'm also rather a fan of take home exams (where you have, for instance, several days complete the exam, something like a super problem set). The time constraints imposed by conventional exams have never seemed to me like a legitimate way to test a student's knowledge of physics.