I took absolutely no offense to your comment… the first line was a joke, the second was just reiterating my point
It comes down to thinking from a theoretical perspective (taking into consideration everything down to a molecule) and thinking from an engineering perspective (only worry about what makes a real difference)… I think it’s fairly clear which approach I take
I thought I explained my reply to the original question pretty well, if there are specific questions I’m happy to try and answer them. I am not willing to give everybody all my work in detail, but I will point to the variables (as I did above) so that people can understand what factors come into play.
With the Lagrangian defined as Kinetic Energy-Potential energy at each point on the yoyo’s path, the only complication i see here is calculating the moment of inertia of the yoyo/axle/bearing/string system. Other than that you can derive all of the equations of motion by the generalized momentum and generalized force that the Lagrangian gives you. We can simplify things by assuming a massless string, axle and bearing though, even though the latter 2 approximations may skew the results a bit.
You can eliminate things like bearing and such so long as you do it across the board… if the idea is only to compare one part to another, things can be off from reality a tiny bit so long as they all are.
The yo-yo physics books I referred to previously cover moment of inertia, radius of gyration, etc. and how to calculate them for yo-yos in a fairly simple way. Of course, advanced computer software like solidworks can do most of the work for you if you know how to use it
