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Re: ACCELERATION



To give a direct answer: I agree with your reasoning. Sudden
change of velocity implies infinite acceleration, which is infinitely
destructive and therefore unphysical. Sudden change of acceleration
does not violate any physical principle, although it may be difficult
to achieve in particular cirmumstances. So the displacement-time graph
need be only twice differentiable.
Regards,
Jack

Adam was by constitution and proclivity a scientist; I was the same, and
we loved to call ourselves by that great name...Our first memorable
scientific discovery was the law that water and like fluids run downhill,
not up.
Mark Twain, <Extract from Eve's Autobiography>

On Thu, 14 Sep 2000, David Abineri wrote:

In talking about displacement vs time graphs in my high school Physics
class it was clear to everyone that displacement must be a
differentiable function in order to represent a real motion. No object
can suddenly (instantaneously) go from one velocity (slope) to another.

Can the same be said for the velocity vs time graph? It seems that it
is possible for an object to go from one acceleration (slope) to another
instantaneously. When releasing an object to free fall the acceleration
goes from 0 to 9.8 at the instant it is released does it not?

Is this conclusion correct? Thanks, Dave Abineri


--
David Abineri dabineri@choice.net