On 11-06-15 09:03 AM, David Jonsson wrote:
On Sun, Jun 12, 2011 at 10:50 PM, Stephen A. Lawrence <sa...@pobox.com
<mailto:sa...@pobox.com>> wrote:
But using the Newtonian mechanics model itself, if you arrive at
the conclusion that the box is lighter when the ball is bouncing,
you can safely conclude that you did something wrong. That's not
a conclusion you can ever get to from the Newtonian model.
OK, sorry, but I also later came with a correction.
Lets change the setup so that the ball bounces sideways. Do you agree
that it now becomes lighter? This is because the centrifugal forces.
The increase and decrease does not balance to zero.
Do you also agree that with the sideways bouncing ball there is also a
small torque on the box, due to the same differences in centrifugal
acceleration?
Dunno -- I'm going to have to think about that one, and I haven't had
the time to really understand it. It seemed wrong when a similar
assertion was first posted (months ago) and still seems wrong to me but
I haven't got a proof that it's wrong, so I could be the one who's wrong.
