Re: weight of a hovering/diving fly in a box

[John Denker <jsd@MONMOUTH.COM>]

At 11:32 AM 9/6/99 -0800, John Mallinckrodt wrote:
> I think you were right the first time.

D'oh!

How 'bout a compromise.  Either version might be true, depending on
(heretofore unclear) assumptions about whether Mr. Fly *pauses* at the top
before diving off.

> The change in the location of the CM is irrelevant.

Specifically: the difference in CM between any two plateaus is irrelevant.
OTOH: if the CM is actively moving at the moment in question, that's relevant.

So:  If the fly is stationary at time t0, dives headlong, smacks into the
floor, and is stationary at time t1, then the average force on the scale
during the interval [t0, t1] must equal the canonical weight of the box+fly.

It's hard to believe it would take multiple iterations to get a correct
statement of such a simple result.  Sigh.