From: Marc Afifi (marc_afifi@yahoo.com)
Date: Fri Dec 03 1999 - 08:14:22 PST
Message-ID: <19991203161422.22803.qmail@web216.mail.yahoo.com> Date: Fri, 3 Dec 1999 08:14:22 -0800 (PST) From: Marc Afifi <marc_afifi@yahoo.com> Subject: RE: Pinhole Digest #300 -- angular displacement
Thanks for the reply John,
Perhaps my question was not clear enough. If I walk 3m
north and 4m west, my distance traveled is 7m but my
displacement is only 5m. This is the actual distance
away from the starting point that we refer to as
displacement. Your reply seems to correlate to the
idea of distance traveled but indeed it is called the
angular displacement in every physics book I've looked
in. My confusion is this: Since there are only 2pi
radians in any circle, the maximum displacement you
could experience would be some angle smaller than 2pi
else you arrive back at the starting point and your
displacement is zero. It doesn't matter how many times
you go around the circle, the displacement is still
less than 2pi from the starting point. The total
angular distance is a different story, but no book I
have seen discusses an angular distance. Is this just
a problem of semantics?
-Marc
--- "J. G. Locke" <lockejg@redshift.com> wrote:
> Go around more than once!
> As in the old 45 rpm records; they go around 90pi in
> one minute!!! oooooh
>
> John
>
>
> ||
> || Subject: Angular displacement
> || From: "Marc Afifi" <marc_afifi@yahoo.com>
> || Date: Thu, 2 Dec 1999 12:46:33 -0800 (PST)
> ||
> || Hi,
> ||
> || Could someone explain how it is possible to
> have an
> || angular displacement greater than 2pi radians?
> Does
> || the word displacement have a different meaning
> in
> || rotational kinematics than it does in linear
> || kinematics? Is there a corresponding term for
> distance
> || in rotational kinematics?
> ||
> || Thanks,
> ||
> || -Marc
=====
Marc Afifi
Chemistry, Physics, Marine Science
Pacific Grove High School
Pacific Grove, CA
http://www.pghs.org/staff/afifi/d5hp.html
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