The book measures 20 x 20.3 x 1.4cm and I'm assuming it's sealed shut so the pages don't flap open. Mass is 450g.
I want to understand how quickly it would fall if dropped straight down from 10km altitude. I've used a value for drag coefficient for a flat plate perpendicular to the air flow that I got from NASA (1.28) but I'm guessing that a falling book would spin round, slowing its fall, so this value is probably not right - is this likely?
So I'm wondering if it's possible to estimate the drag coefficient to any degree of accuracy. I don't have access to a wind tunnel and I'd rather not drop it off a tower as an experiment. :)