Solution
The answer to the case posed is:
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wind speed
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=
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60.116682375170416309877829
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|
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754301675338292926083413 mph
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This number is easily obtained by root-finding on the formula that answers the second part. For the second part, the time in terms of air speed, wind speed, and radius is given by
(4 r v E[w²/v²])/(v² − w²)
Here, E is the complete elliptic integral of the second kind.
The derivation of this formula given by Michael Elgersma is quite elegant, and simple.
Correct solutions were also submitted by Richard Boardman, Witold Jarnicki, David Broadhurst, and John Sullivan.
[Back to Problem 1200]
© Copyright 2015 Stan Wagon. Reproduced with permission.