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Re: Tanx To U All....
Forum List  Follow Ups  Post Message  Back to Thread Topics  In Response To Posted by Jim Bergquist on February 24, 2001 05:04:37 UTC 
In regards to the article that you refer to, for an object in circular orbit the radius of the orbit remains constant. Hence the radial velocity and acceleration are both zero even though the xy motion is sinusoidal and therefore exhibits changes in linear velocity and linear acceleration. The relation between the radius and the xy coordinates is r² = x² + y². For a circular orbit, x = r*cos(theta) and y = r*sin(theta). theta = w*t where w is dependent on the radius of the circular orbit. If r = 6400 km, the Earth's radius, at theta = 0, then x = 6400 km and y = 0 km. A quarter of the way around the Earth, theta = 90 degrees and x = 0 km and y = 6400 km. But for both positions, r = 6400 km; there is no change in the radius.


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