Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site sdcc3.UUCP
Path: utzoo!linus!decvax!ittatc!dcdwest!sdcsvax!sdcc3!ewa
From: ewa@sdcc3.UUCP (Eric Anderson)
Newsgroups: net.puzzle
Subject: Re: Polar paradox (SPOILER?)
Message-ID: <3119@sdcc3.UUCP>
Date: Sun, 29-Dec-85 05:40:32 EST
Article-I.D.: sdcc3.3119
Posted: Sun Dec 29 05:40:32 1985
Date-Received: Mon, 30-Dec-85 03:21:14 EST
References: <2667@sunybcs.UUCP>
Reply-To: ewa@sdcc3.UUCP (Eric Anderson)
Distribution: net
Organization: U.C. San Diego, Academic Computer Center
Lines: 25

In article <2667@sunybcs.UUCP> colonel@sunybcs (Col. G. L. Sicherman) writes:
>Here's a new one: a practical joker tampered with the Great Explorer's
>gyrocompass, so it points 45 degrees off.  The Great Explorer thinks
>he's going due north on his way to the North Pole, but he's really going
>due northwest!
>
>Will he reach the North Pole anyway?  (Geographers keep out of this one!)

I'm no geographer, so...

If a 'gyrocompass' is no different from a normal compass, it is impossible to
tamper with it in such a way as to make it point 45 degrees off. Consider:
1. The orientation of the NSEW scale is not important, since you line up the
   needle with 'N' each time.
2. The needle is magnetized along its major axis. While a 180 degree error
   could be introduced, a 45 degree error cannot.

If a 'gyrocompass' is such a device that it can be mis-aligned by 45 degrees
despite the above, then our explorer will spiral in to the pole, assuming he
checks his direction constantly.

(Well, the north MAGNETIC pole, not the one we all think of.)

Eric Anderson, UC San Diego         {elsewhere}!ihnp4!ucbvax!sdcsvax!sdcc3!ewa
Home: (619)453-7315       Work: (619)586-1201       White House: (202)456-1414