1S20.10 • Angular Momentum: Orbital Speed

Photo shows the demonstration used at the University of Texas at Austin.

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Instructions/Notes:

• Hold demo out so as you begin to rotate the ball, the class should be able to see the orbit.
• To simulate different levels of gravity and radius of orbit, pull the string in the center towards you. You should be able to see the speed of the ball increase the smaller the radius gets.

Concepts Conveyed:

• Kepler’s third law: The period it takes an object to rotate around a center of gravity depends on the radius between the object and that center of gravity.

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Video shows the demonstration used at the University of Texas at Austin.

Last updated on January 27, 2025