So, I hear you are starting your second semester of physics. One of the cool things about physics is that the second semester still uses stuff from the first semester. Maybe you forgot some of that stuff, so here are the bare essentials you will need to get by (this is assuming you are in the algebra-based second semester of physics)
Vectors
Really, just about the entire semester course is about the electric and magnetic field. Both of these are easiest to represent as vectors. So, you pretty much need to know how to deal with vectors. Here are some reviews:
Momentum and Forces
Honestly, this isn't a big one. You will probably need to know about forces and the momentum principle (or Newton's second law if you prefer to call it that) just because it will be part of an application.
Work-Energy
This is much more important than momentum. You DO need to understand energy. When you talk about circuits and electric potential, there is energy all over the place. Here are some review links:
So, those the big ones. If you are having trouble with that, work on it. Trust me, it will help you succeed in the second semester physics.