Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!cbatt!cbuxc!cbuxb!cbrma!aka
From: aka@cbrma.UUCP (Andy Kashyap)
Newsgroups: net.puzzle,sci.physics
Subject: Re: Funny Orbits
Message-ID: <5333@cbrma.UUCP>
Date: Fri, 24-Oct-86 14:22:56 EDT
Article-I.D.: cbrma.5333
Posted: Fri Oct 24 14:22:56 1986
Date-Received: Sat, 25-Oct-86 07:04:47 EDT
References: <352@linus.UUCP>
Reply-To: aka@cbrma.UUCP (Andy Kashyap)
Distribution: net
Organization: AT&T-BL, RMAS, Columbus
Lines: 37
Xref: watmath net.puzzle:2104 sci.physics:49

In article <352@linus.UUCP> bs@linus.UUCP (Robert D. Silverman) writes:
>A new orbit puzzle:
>
>Assume that an object in a circular orbit suddenly has its mass cut in half.
>What happens to the orbit?
>
>By the way, the factor of 2 in the above question is critical. If it is
>greater than 2 something else happens and if it is less than 2 something else
>happens.
>
>Bob Silverman

There is some confusion. If by "mass cut in half" you mean, half the mass
suddenly vanishes then the answer is "nothing". Orbits have nothing to
do with masses (excepting relativistic effects), but with velocity and
altitude alone.

On the other hand if you mean, the mass somehow explodes in two equal masses
then the answer is more interesting:
There must be conservation of angular mementum. So the center of mass of
the two mass system will continue as before. Now, if the two masses are
moving apart then (by conservation of linear momentum) one must be moving
faster than the center of mass and the other slower. They both will end
up in a elliptical orbit. The faster one in a more eccentric orbit than the
slower one. However, if the explosion is strong enough, the faster one will
spiral out of the system forever, and the slower one will spiral in and
collapse. In this case, what happens to the center of mass? BEATS ME???

Oh well, I tried.
-- 

+---------------------------------------------------------------------------+
: What is reality anyway but a collective hunch.       : Andy Kashyap       :
: Reality is fine in small doses ...                   : AT&T Bell Labs     :
:     ... but as a life style, it's too confining.     : Columbus OH        :
:                              -- The Tonight Show     : ..!cbosgd!cbrma!aka:
+---------------------------------------------------------------------------+