Re: Again :-] : Re: Again: origin of bird flight

["Tim Williams" <twilliams_alpha@hotmail.com>]

Jim Cunningham wrote:

> > For all other predators, the time it takes to fall is not too different
> > between whether the height is 1m or 2m above ground.  I could do the 
> math, [snip]
>
> Assuming no lift:For 1 meter, 0.451 secondsFor 2 meters, 0.639 seconds
> A difference of 0.187 seconds or a 29.3% difference 100*(1-0.5(2)^.5)

Thanks Jim.  (By the way, is that in a vacuum, or did you take into account 
wind resistance?)

That 0.187 seconds probably isn't going to be enough time for the prey to 
flee the scene (unless, again, it happens to be Road Runner).  Also, the 
time for the fall would be increased by drag surfaces on the predator.  This 
would be an advantage for the leaping predator - allowing better guidance 
and positioning during the fall.


Tim


------------------------------------------------------------

Timothy J. Williams

USDA/ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163

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