> W L Wrote:
> ...FYI - for anyone who is thinking of removing the other three weights,
> there a bit of an improvement in acceleration. I might get 6 equivalent
> weights to balance everything out evenly.
This is a good thought experiment (re: balancing of 6 over 3 weights). Without getting too technical, as long as the magnitude of the vectors (force of the weight on the disk) sum to zero (which they should if all the weights are the same, and evenly spaced), then the number of weights shouldn't matter (as long as there's more than 1, using planar-Euclidean geometry & ~ high-school physics principles). That said - no system is entirely perfect, and more points to position mass (with the attempt being as evenly from the center as possible), will result in more uniform moment of inertia around the circumference of the disk. More mass (applied evenly) will also increase the moment, and smooth/balance action.
But, at a very micro level, the radius of the weights from center will differ to some degree, even if only micrometers, not to mention the fact that the disk is fixed perpendicular to the axis of rotation along the z axis (enter gravity); spacial movement is much more complex than planar. Still these variables should be negligible for our purposes.
Now what about if three weights (masses) are of one type, X grams, and 3 of another, Y grams? The heavier weights will apply more outward force (and themselves, require more force to move). But since the force needed to move the belt is (assumed to be) uniformly applied to the disk at any given moment (this is not technically true, as it does not touch the entire circumference), then the differences in mass should not matter. This also assumes that the force of the lower mass weights is not sufficient to move the belt / variate, and/or that any of the masses at rest could do the same (very unlikely for our purposes).
Ugh, what a tangent. Hope someone finds this at least interesting (but prob not, you all seem smart anyway). (edited)