He's saying the center of mass won't move. Which is what he said. The pipe can still move, just not the center of mass of it and its contents.


Originally Posted By: paul
Quote:
The center of mass of the whole system - i.e. pipe + mass - will not move, as observed by an outside observer.


so your saying that if Im standing outside of the pipe I would not notice that it moves , because it will not move.

correct?