>
> I have a sphere, falling from 20 feet, and assuming a vacuum.

Assuming Earth surface gravity and zero initial velocity, then
it will take about 1.118 seconds to fall and be traveling at
just under 36 ft/sec when it hits.

> What deceleration do I need to I need to design to?
> A thumbnail analysis suggests over 2000Gs, but that seems way
> excessive.

Insufficient information to compute answer.

Deceleration depends on what distance is used to stop the object --
direct impact on concrete floor, distance will be very close to 0
while if contained in a frangible cardboard box, it has several
inches in which to disipage the energy as cardboard deforms.

						Lee

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