On 16 Jun 2004 14:42:37 GMT, (JMartin957) wrote:
Relative orbital motions can boost that into the 20 to 40 miles per second
range, or slow it to only a few miles per second, depending on the exact
geometry. But even an object at relative rest at 200 miles above the surface
would acquire a final velocity of around 5 miles a second by the time it
reached the surface.

Gary:

You didn't mean 2,000 miles, or maybe .5 miles/second, did you? I did some
quick back-of-the-envelope calculations, with the assumption that gravity is a
constant regardless of altitude. Which of course it isn't, but it makes things
easier.

Not that I normally check things like that, but when I saw 200 miles and 5
miles per second, and thought "OK, that's 80 seconds", it seemed like too high
a final velocity for only 80 seconds.

Agree with all your other points, though.

John Martin

Yeah, you got me on that, John. 5 miles a second is orbital velocity at 200
miles. An object at relative rest won't have orbital velocity, of course. I get
a value of 257 seconds for the fall, with a final velocity of 1.557 miles per
second. Of course that ignores the atmosphere. It won't actually reach
that speed due to the effects of drag.

Gary