Blog / Deep and profound brain things inside my head

Murderous Physics

April 2, 2012 - Cutaway, Infographic, Movie Infographic

I’m beginning to find subjects that I hated in school to be interesting now. Especially math. And I can thank film for this interest. After reviewing some simple math (Shawshank Redemption, Dexter’s Victims), I’ve started to explore other concepts.

Free Fall

The chainsaw scene in American Psycho is both terrifying and comical: the protagonist chases his victim, and then times a chainsaw drop from the top floor, striking his victim below at the right moment. I saw a comment on youtube that mentioned the physics behind the scene, so I just had to figure out the science for myself:

Khan Academy could not have predicted this as a result of their instructions, but I actually relearned a lot about free fall through this graphic.

I’m sure Patrick Bateman did not practice chainsaw drops to perfect his timing. And although free fall equations are simple enough, does he remember them? Can he take roots of numbers besides perfect squares without a calculator? Not to mention the conversions between metric and imperial. So was the hit was just pure luck (or imagination)?

I simplified the scenario here, not taking into account rotational force, drag coefficient etc., to see if it was possible to crunch numbers on the run. It seems possible, since Bateman had about four flights of stairs to calculate. There are also some logical and architectural fallacies in the scene though, most notable of which is Bateman releasing the chainsaw when the victim is on the second floor, not the first. Drama > Science. But, the part that mattered to me in this graphic (math) worked out.