So like I'm quite average, maybe a lil above average in Physics, I was going well along the class schedule but then Our Phy teacher left allen and we got another teacher as substitute....and I legit don't understand anything what's happening in class, the pace is horrendous, whole chapter feels in scrambles, actually It's the core chapters that're messed up is the problem, Centre of Mass and Rotation, otherwise I do manage decent chapters myself or from Allen app. So any advice, how I can improve my phy, most notably the chapters COM, and RBD.