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Re: da/dt = jerk?

On Mon, Nov 08, 1999 at 05:54:32PM -0500, Robert A Cohen wrote:
P.S. I saw nothing in the archives that addressed the ball rolling down a
circular ramp (which then "bumps" when it meets the horizontal surface).
I'll assume the bump is due to the difference in rotation vs. translation
rates, unless anyone corrects me.

BTW: I have read in an analysis book that rail bends have are not just parts
of circles, but other curves, because coming into a circle would mean a
sudden change in the normal component of acceleration. The author's idea was
that, although the speed doesn't change with a step, a sudden change in the
acceleration (appearance of a force) is, at least, unpleasant (is that
really a problem? I mean, the maximum value of the force/acceleration is the
same anyway, well, if the bend is long enough; or is the sudden change "bad"
enough, e.g. because of the wide spectrum?).

Bye
Guentcho