@S1-A.ARPA,@MIT-MC.ARPA:MILLER@YALE.ARPA (07/12/85)
From: David Miller <Miller@YALE.ARPA>
The reason the IMAX camera is difficult to move is due to the
"gyroscopic effect" put on the camera by the rotating film
reels. This was pointed out in the original article. All
of the suggestions having to do with counter rotating reels
will not diminish this effect at all. Angular momentum has
direction and can be cancelled by an equal amount in the
opposite direction. "Gyroscopic effect" is due to INERTIA
and is a magnitude independent of direction. Marion's
"Calssical Dynamics" Chapter 12 has a good explanation on the
subject. But for a more intuitive situation think of two
gyroscopes rotating in opposite direction. Now attach their
outer frames. The outsides will stop rotating, but the
gyroscopes will not topple over (as a cancellation of gyroscopic
effect would indicate). Instead, the entire system is more
stable than its parts.
Inertial guidance systems have relied on this for years. They
are crammed full of gyroscopes in all orientations and rotating
in different directions.
--David Miller
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