IBM Active Protection System Approach

[Julian Elischer]

M. Warner Losh wrote:
> In message: <430A8E2B.6040408 at elischer.org>
>             Julian Elischer <julian at elischer.org> writes:
> : You have about 1/4 a second to get the heads in once you detect that
> : you are falling.
> 
> Yes.  For a 4' fall, we know it takes 1/2 a second to reach the
> ground:
> 	s = 1/2 a t^2 + v0 t + s0
> 
> s0 = 0, a = 32 f/s^2, v0 = 0, s = 4, solve for t gives 1/2 a second to
> make the fall.  Sos was saying 10's of ms to retract the heads, so
> even a 300ms response time wouldn't be fatal, but it would be pushing
> the limits.
> 
> For a 2' fall, you have even less time.  More like 350ms.  1' is 250ms...
> 
> Warner


I decided that you assume it's being picked up and slips out of your grasp
and then dropped a pen from about 2' and said
"yep, something like 1/3rd of a second.. I'll say something shorter than that" :-)