Random Musings

[Wubbly]

Perhaps an explanation of what Jonathan was talking about in this picture here:
http://www.besslerwheel.com/forum/viewt ... 3240#53240

When a mass is traveling at a certain radius in a rotating system, and then travels to reconnect at a larger radius, a large portion of the velocity is lost. The portion of the velocity that is lost is along the line of the new radius, and is perpendicular to the new tangent velocity. You would loose linear tangential momentum at the new radius. Working out the geometry results in conservation of angular momentum. In this case, linear tangential momentum and angular momentum can not both be conserved and it's the linear tangential momentum that looses out.

[Tarsier79]

You can reduce this effect by forcing the weight to move in a spiral.

OOps, should have looked at the link. Regarding the cylinder and spheres: I guess the change in direction compared to cylinder rotation changes the way in which the spheres act on it.

As an example of yo-yo de-spin, on the Dawn Mission, roughly 3 kg of weights, and 12 meter cables, reduce the initial spin rate of the 1420 kg spacecraft from 36 RPM down to 3 RPM in the opposite direction[1]. The relatively small weights can have such a large effect since they are far from the axis of the spin, and their effect grows as the square of the length of the cables.

It would be nice to know inertia of the rocket+ initial radius of the weights.