- This thread has run its course. You will find newer threads in the discussion section.
Another discussion thread - the fourth - has reached the (arbitrary?) 500 comments threshold, so it's time for a new thread for Eliezer Yudkowsky's widely-praised Harry Potter fanfic.
Most of the paratext and fan-made resources are listed on Mr. LessWrong's author page. There is also AdeleneDawner's collection of most of the previously-published Author's Notes.
Older threads: one, two, three, four. By tag.
Newer threads are in the Discussion section, starting from Part 6.
Spoiler policy as suggested by Unnamed and approved by Eliezer, me, and at least three other upmodders:
You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).
If there is evidence for X in MOR and/or canon then it's fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that "Eliezer said X is true" unless you use rot13.
It would also be quite sensible and welcome to continue the practice of declaring at the top of your post which chapters you are about to discuss, especially for newly-published ones, so that people who haven't yet seen them can stop reading in time.
It seems that they might act in a hybrid Aristotelian/Newtonian manner. Certainly in canon they talk about broomsticks having maximum speed not maximum acceleration. And people have trouble pulling from being near to hitting the ground, something which sort of makes sense in an Aristotelian framework because objects want to go to the ground.
Outside canon, the movement of the broomsticks in the movies does seem to be a definite mix but this is likely more due to standard movie physics than anything else.
It makes sense by postulating that a broomstick always goes where it's pointed (no Newtonian momentum), but there is a maximum angular speed for turning the broomstick. The rider applies force to turn the broomstick, which means there's resistance, so it's not difficult to assume that the resistance creates an effective maximum angular speed.
This doesn't sum up to Newton, of course, because this maximum angular speed isn't dependent on current linear speed.