Re: [Phys-l] Rocket Science

[Jack Uretsky <jlu@hep.anl.gov>]

Hi all-
	A cute, non-trivial question.  I assume, from the wording of the 
question, thet the increase in speed is instantaneous and that the orbits 
are large enough so that "directed toward spacecraft #1" means "tangent to 
the circular orbit."  Then spacecraft #2's orbit is no longer circular, 
but is an ellipse, tngent to the circular orbit of spacecraftt #1 at the 
point where the speed increased.  The minor axis of the ellips is the 
radius of the circular orbit.  How big  is the major axis, and what 
conservation law determines its value?
	A good text for this problem is "The Mechanical Universe", 
standard edition.
				Regards,
					Jack


On Tue, 25 Jul 2006, John Denker wrote:

> Hi --
>
> A classic question:
>
> Here's the scenario:  Spacecraft #1 is launched into a nice, circular,
> low-earth orbit.  Shortly thereafter, spacecraft #2 is launched into
> the _same_ orbit.  At this point in the story, spacecraft #2 is keeping
> pace with #1, and is simply 90 km in trail.
>
> The flight plan calls for the two craft to rendezvous.  At time t,
> spacecraft #2 fires its thruster, thereby giving itself a delta v
> of 60 km/h, directed toward spacecraft #1 in the obvious way.
>
> Here's the question:  Within a km or so, how far apart are the
> spacecraft at time t + 90 minutes?
>
>
>
> Vis vobiscum.
>
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