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Spinning Bike Wheel and Conservation of Angular Momentum

Holding a spinning wheel doesn’t sound that perplexing, but when you hold a spinning wheel while standing on a turntable, something surprising is revealed. Watch as MIT alum Ryan Robinson demonstrates the Spinning Bike Wheel and Conservation of Angular Momentum for MIT Physics:

Now, Newton’s Third Law says that for every force there’s an equal and opposite force acting as well. So when I force the wheel, the wheel is applying force equal and opposite onto me, causing me to turn.

So the same thing applies when I’m on the ground, but the friction between my shoes and the ground stop me from spinning.

spinning wheel
Next, Robinson introduces conservation of angular momentum, “something that tells you how hard it is to either start or stop something from spinning.”

And it depends on two things: 1. How fast it’s spinning—we call that the angular frequency—and 2. Its shape. We call that the moment of inertia.”

This MIT Physics demo from 2017 can be found on the MITK12 YouTube channel, an archive of original STEM videos for K-12 students made by MIT students.

spinning demo
spinning wheel demo: +L
Find more MIT K12 videos at k12videos.mit.edu.

Then watch more physics demonstration videos about the science of spinning, including:
• Angular momentum demo with a Hoberman Sphere
• Dance & the physics of rotation
• How A Children’s Toy Led To An Essential Medical Device
• Earth’s Rotation and Revolution + Following the Sun
• Extreme Gs in a centrifuge: Simulating gravity on other planets

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