Let's calculate the angular momentum in the two extremes (assuming a thin cylinder and small balls with respect to cylinder radius R):
The kinetic energy:
Since angular momentum and energy have to be conserved, we get two equations from which and can easily be calculated:
Now let's look at the linear momentum:
As you see, there is no linear momentum. Could you clarify how you would make the calculations with linear momentum if there is no linear momentum?
note: earlier, I assumed a quasi-static system where the balls are released slowly and remain at the same orientation with respect to the central mass, in that case there is indeed a loss in kinetic energy. There are no significant losses in the system in the video.
Edited by Bender, 20 January 2017 - 09:47 AM.