Finally finished Ch. 3! I got very lazy with the exercises (did one, couldn't do two; got bored near the finish line with the last) so I should come back to that at some point. I did not really follow any of it, which is probably partly because I started it something like 9 months ago and kept taking multi-month breaks. Another reason I did not follow it is that I am not very good at physics :(

Anyway, onwards!