8/14/2023

 Hi, 

Oops.

I haven't been posting for a while.

Anyways, I started the Angular Momentum chapter in HRK today, and two things gave me a headache:

1) gyroscopic precession

2) which axes (accelerating, non-accelerating, etc.) ${\tau }_{\text{ext}}=\frac{dL}{dt}$ is true about

With some online help, I was finally able to grasp these two things. The answer to the second question is that the equation only works for non-accelerating axes, unless in the special case that the origin is the center of mass. Using the derivation for the equation, it's clear that the reason it fails for accelerating axes is because $F=\frac{dp}{dt}$ isn't true for those. However, I'm still trying to prove why it does work for the CM, even when the CM is accelerating. I'll make a post about this once I'm able to prove it.