| Chronology | Current Month | Current Thread | Current Date |
| [Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
It seems to me that one _can_ imagine that the change from 0 acceleration to
that due to gravity (say 9.8 m/s^2) could happen in an _extremely_ short
time (arbitrarily approaching zero). What I imagine is a hard steel ball
being held at two points on its horizontal circumference by a spring loaded
clamp that has point like projections which make the actual contact. Now if
the ball slips, it immediately loses contact. I can imagine the spring to
be as strong as needed to release the ball _very quickly_. In this thought
experiment the ZAP (da/dt) approaches infinity. OK--in a _real_ situation
the clamp will make tiny indentations in the ball so that there can be some
tiny frictional slipping during release and one can even propose some
electrical interaction between the clamp and the ball that decreases rapidly
with separation.
I think the original point was that unlike changes in velocity which can be
instantaneous only with an infinite force, what really prevents
instantaneous changes in acceleration (infinite zaps)?