Member-only story
Modeling a Spinning and Flipping Handle Using Springs and Python
I don’t think that title really explains the problem. It’s called the Dzhanibekov Effect — but that doesn’t really help either. How about this? Imagine you are in the International space station and you unscrew a t-handle really fast. Once the handle leaves the thread, it’s just floating there and spinning. Then this happens (here is the YouTube version):
Isn’t that crazy? I mean, it’s crazy awesome. It goes against our basic physics intuition. We see this thing spinning and there’s clearly no torque on it — then how does its angular momentum change? The answer is: it doesn’t. Ha.
It all comes down to this definition of angular momentum:
Yes, L is the angular momentum vector and ω is the angular velocity vector. Finally, I is the moment of inertia. We like to think of this equation as being very similar to the linear momentum equation:
So, if ω is like the velocity and L is like the linear momentum, then I must be like the rotational mass — right? Actually, that’s a pretty nice name for it. But here is a huge mathematical difference between these two. In the linear momentum equation, m is a…
