Physics itself is very challenging conceptually. Even if you pay attention in class it still might not fully click for you. Youtube channels I recommend are Walter Lewin and Chad's prep. You could also email Mr Z with questions since he responds to emails very quickly. The tests are pretty hard just because the concepts are hard. On the tests there are usually a few mcq and a few frq, with the mcq's being conceptual questions and frq's being problems to solve. All the formulas are on the formula sheet which is provided on all tests and quizzes. Mr. Z doesn't assign any required homework but everytime we learn a new concept we get a worksheet with a bunch of problems which I recommend doing as soon as you are handed them because the class moves fairly fast and you don't want to be stuck on the basic concepts as you progress further into a unit. Mr. Z gives checkpoints, which are usually less than 4 questions. If you get anything wrong, you can do corrections until you get everything right and your grade will be changed to 100%.