Physics

Hi, I’m using more the “common” terms that most yoyoers are familiar with so others can actually understand what exactly we’re talking about.

Let me clarify here:

Axial Stability (or just “stability”) → the perceived reaction moment when an axis-change torque is applied
Sluggishness → linear inertia
Weight distribution → radial and lateral distribution

Now, let me reiterate:

  1. The behavior of the yoyo in translation is strictly governed by the linear inertia and the elastic modulus of the string.

  2. On the end of the string, the weight distribution can NOT be judged from the yoyo’s linear behavior

  3. I specifically stated that the shapes of the yoyo is assumed to be identical for the discussion here, because we are only comparing the weight distribution and its effect on its linear behavior.

  4. The yoyoer can perceive the weight distribution indirectly from the reaction moment felt when changing the axis of rotation.

EDIT: Parallel Axis theorem says I’m wrong. But I’ll keep the originals anyways.

I would assume that distribution is a rather impossible thing to calculate through just plain eyes…but somehow, when I play with supposedly stable yoyos, the best place for more weight is 1/3 of the yoyos half going from bearing out. At least this is the case for the wasabi and popstar. They have nearly the same profile, the same weight, but are totally different sizes. The wasabi feels more stable to me, and it follows this rule, I am fairly certain. The popstar is still a great yoyo, but has the opposite distribution, and plays extremely heavy due to said fact.its most mass is near the rims for a reason. Still are both great yoyos. I barely know college physics, and only some calculus. But those are my thoughts based off ap physics.

Second semester tells me that you are correct, but not because of the argument you presented (or maybe you have, but it escaped me completely). My impression of what you were saying is that the problem is too complex to draw any simplified conclusion, which I disagree because the other factors are not entirely relevant if we make a few reasonable assumptions, which was the basis of my arguments previously. The first of these is the assumption that the yoyoer is skilled enough to keep the yoyo in a reasonably 2D motion. This I made this assumption because the torque of changing the rotation axis is a reasonably small portion in perceived resistance against the player’s exertion. The discussion here is on the strange phenomenon of perceiving a difference in the exertion required by the player to change the motion of an object with the same mass but different distribution.

Now let me point out the fallacies in my previous post. Actually, the argument I presented are still still perfectly true, but they are not valid for the situation because I did not realize an important fact: that the motion of the yoyo are primarily rotations rather than linear translations. To be more accurate, the motion includes both components of rotation and translation that are comstantly changing, but for the purpose of our discussion we can simplify it to a scenario of a constant radius circular motion. Suppose the player is doing a pinwheel with constant radius and then hitting the yoyo onto a trapeze to change the direction. When simply doing the pinwheel, Newton’s 2nd law of motion applies to the centrifugal force felt by the finger, which is the same regardless the weight distribution as long as the total mass is the same. But this is where the validity of my previous argument ends. As mentioned earlier, we could reasonably ignore the change in axis as a factor because this is a very minor and infrequent component of yoyo play. However, there is one significant component of yoyo play which I have not considered: wh

You guys also forget that the yoyo doesn’t move on it’s axis; it’s always a little off.