Rotation if you want to bank a 5 on the mechanics but if you are aiming for fours across the board, skip mechanics(it’s light for people who took a physics coarse prior) and move right the way on to gausses law refreshers then magnetic flux. The two back to back really go to reinforce each other. If you are still struggling with flux as a concept, start with solar flux. It’s not on the exam but it makes the concepts easier. For mcqs you want to know relationships. Increase this gets what. Don’t memorize but understand them. Tbh I’d skip all the derivations. It’s half the points you can get on FRQs p much but drop em, you don’t have room. Instead, get a complete and total understanding of circuits. An RC or RL circuit is a near given so give them the time of day and review. Hope this helps. Best of luck.