lecture 5-6c: gyroscopic motion - iti resources · 2016-03-07 · gyroscopic motion is the...
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Conservation of Angular Momentum
In the absence of any external torques on a system:
Angular momentum conservation preserves both the spinning rate AND the orientation of an object
Gyroscope for the International Space Station Credit: NASA https://en.wikipedia.org/wiki/Control_moment_gyroscope#/media/File:ISS_gyroscope.jpg
The Earth is a spinning body Credit: NASA https://commons.wikimedia.org/wiki/File:1_Earth_(blank_2).png
Bicycle wheels have angular momentum Credit: Andy Armstrong: https://en.wikipedia.org/wiki/Mountain_biking#/media/File:Mountain-biker-climbs.jpg
Spinning top by Dhor https://upload.wikimedia.org/wikipedia/commons/5/57/Snurra_uppochner.gif
Some really fun toys!
Gyroscope animation from giphy.com: http://giphy.com/gifs/gyroscope-F62lPOGDf5XzO
Some really fun toys!
Accelerations change direction of motion
x
y Constant circular motion requires a centripetal acceleration to change the velocity direction
Gyroscope animation from giphy.com: http://giphy.com/gifs/gyroscope-F62lPOGDf5XzO
The precessional motion of gyroscope is the reorientation of the angular momentum vector by
gravitational torque
Precession of the Earth
The Earth's rotational axis points toward the North star, but its orientation precesses every 26,000 years
The North star won't always be due North!
Credit: Kevin Hadley https://en.wikipedia.org/wiki/Celestial_pole#/media/File:Star_Trails_Shoreline.jpg
The angular momentum of a spinning object points toward its orientation; an applied torque can change that orientation
Gyroscopic motion is the rotational equivalent of circular translational motion - a rotational orbit
Many spinning objects, including the Earth precession and change orientation due to external torques
Summary
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