I 'm thinking that the gradient on both sides is due to the increase/decrease in light as the object moves into/out of the field of view. When the whole object is visible the image is exposed the same as it moves across the field and is the brightest.
The exposure of the central section looks approximately the same as in the exposures between 1/15 second and 1/30 second; during that time it traveled one inch. So I claim that its speed is between 15 and 30 inches per second.
-yoram gelman
-------------- Original message from ADavidhazy <andpph@xxxxxxx>: --------------
> My students will be taking final exams tomorrow. You can review and
> ponder about one of the questions (for entertainment value!) at the
> following URL: http://people.rit.edu/andpph/a-pix/2009-sensi-1.jpg
>
> click!
> andy
>
