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Re: interesting pic for a classroom exercise?



Stefan is pretty close with his back-of-the-envelope calculation. And I loved the picture!
A check of a few web sites and links turned up a drawing for an aircraft (MD-11) that looks pretty much like the one in the photo.:

http://www.boeing.com/commercial/md-11/ext.html

The length of the MD-11 is 200'11" or 202'2", depending on which engine is has. That probably isn't as important as whether it is viewed at a slight angle rather that perfectly edge on in the photo. Taking the length as 200 feet, and assuming the view is close enough to edge on, the distance I caluclate is 25 miles. This is a great application of the "small-angle formula" that is in the astronomy text by Kuhn: W = (Theta-degrees)x(distance)/57.3.
Rondo Jeffery
Weber State University
Ogden, UT 84408-2508



jeglin@4PI.COM 01/26/01 01:29PM >>>
<http://perso.club-internet.fr/legault/s010113.jpg>

Q: how far away is the plane from the camera?

My zeroth-order back of the envelope, unchecked, rough estimate, is
30 mi. Seems reasonable, but this depends linearly on the assumed
length of the plane in my approximation. People familiar with
airliners can probably recognize the plane immediately and know its
length...


Stefan Jeglinski