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From: guy@slu70.UUCP (Guy M. Smith)
Newsgroups: sci.physics
Subject: Re: Acceleration vs. Gravity
Message-ID: <320@slu70.UUCP>
Date: Tue, 28-Oct-86 13:54:52 EST
Article-I.D.: slu70.320
Posted: Tue Oct 28 13:54:52 1986
Date-Received: Wed, 29-Oct-86 22:46:58 EST
References: <6108@decwrl.DEC.COM>
Organization: Saint Louis University, St. Louis, MO
Lines: 18
Summary: gravity inside earth

In article <6108@decwrl.DEC.COM>, wasser@mosaic.dec.com.UUCP writes:
> 
> 	1) The acceleration is stronger at the bottom of the
> 	elevator because the bottom is closer to the center of
> 	gravity.
> 
> 	2) Two plumb lines will converge slightly because both strings 
> 	point toward the center	of gravity of the mass.  The strings
> 	would hang parallel under acceleration in space.
>  
> 	Warning: Experiment 2 can probably be fooled by appropriately
> 	shaping the large mass.
Actually, Experiment 1 can also probably be gimmicked. The gravitational
acceleration within the earth doesn't change much until you get to the
core-mantle boundary. This basically occurs because the core is much denser
than the mantle so that the fact that you have less mass under you as
you go down is compensated by the fact that you are closer to the dense
core.