I did the chapter on 2d and 3d motion, which included relative vectors, drag forces, circular motion and the derivation of centripetal acceleration—which was pretty straightforward. The centripetal acceleration uses the “small-slice” technique where you consider an infinitesimal portion of a circle, a commonly used technique in physics derivations. I then did the multiple-choice questions, and started some free-responses the setups were pretty unconventional which made great practice.