🚀 go-pugleaf

-From: gene@wucs1.wustl.edu (_Floor_)
-Subject: Re: Acceleration
-Date: 29 Dec 92 16:22:35 GMT

-In article <C00wHv.HK7.1@cs.cmu.edu> roberts@cmr.ncsl.nist.gov (John Roberts) writes:
-] -Small force? I think they said the probe would feel an acceleration of 350 g's.
-]                                                         ------------
-] -It's receiving a force 350 times that of Earth's gravity at the surface of
-] -the Earth. That's quite a bit of force if you ask most people.
-]                                   -----
-]  
-] - Gene Van Buren, Kzoo Crew(Floor), Washington U. in St. Lou - #1 in Volleyball
-] 
-] Acceleration and force are not the same thing. In this case, acceleration
-] is force *per unit mass*. If you can keep the mass down on any given 
-] component, then the force isn't too great, even under high acceleration.

-F=ma, right? So if the mass is the same, then an acceleration 350 times
-that experienced on earth is due to a force 350 times that on earth, right?

That's right. So if you can make "m" small enough, then you can keep "F" 
manageable even if "a" is large. Of course, strength also decreases with
decreasing mass, but not linearly - I believe strength per unit mass generally
increases with decreasing size [2]. So if you scaled an ant or daddy longlegs
spider up to a mass of ten tons, the poor critter wouldn't be able to move
(numerous science fiction films notwithstanding). If you dropped Big Ben
onto a concrete surface, it probably wouldn't fare as well as a wristwatch
subjected to similar acceleration. :-)

[2] There are at least two relevant factors - the square-cube law, and
surface effects.

John Roberts
roberts@cmr.ncsl.nist.gov