MIT Physics: Spinning Bike Wheel and Conservation of Angular Momentum
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it as the standard demonstration of angular momentum conservation when asking or answering questions about why the person rotates once the spinning wheel is flipped.
Recommended by 1 people across 1 different months, 2018 to 2023.
What it is
A 2-minute MIT K12 demonstration in which host Ryan Robinson spins a bicycle wheel, then flips it over while standing on a rotating platform and starts to turn. It explains the effect through conservation of angular momentum, with animations.
What people said
Recommends Farcher · 2018-08 · Physics Stack Exchange · on “Conservation of Angular momentum during inversion of a rotating wheel”
The first thing to note is that if the angular momentum of the flywheel was large then it is unlikely that the inversion of the flywheel could be done one-handed. Such demonstrations [this video] are often done with lead loaded bicycle wheel with two handles held by hands on either side of the wheel. There are a number of forces involved in a 3D space so I have had to annotate two diagrams to try and explain what is happening. First of all the axis of rotation of the flywheel has to be moved from the vertical. This is done by applying a torque (forces $F1$ and $F2$) to the flywheel as shown in the left hand diagram. The anticlockwise angular momentum of the flywheel (and person) is changed becaus
Cites Space Thoughts · 2020-03 · Physics Stack Exchange · on “Confusion About Conservation Of Energy When Analyzing This Experiment”
The video here [this video] shows a clear demonstration of conservation of angular momentum. Given the experiment is performed within an isolated system, these are my thoughts: The spinning bike wheel continues (if no friction) to have the same rotational kinetic energy during the whole experiment. When the guy in the video starts to rotate, the additional rotational kinetic energy must come from the guy, there is no other option, if the total energy must be conserved. The guy uses not only energy to turn the wheel, but also to make himself rotate. Where does the rotational kinetic energy of the guy rotating goes, when he stops the rotation? It dos not convert into new kinetic energy. It dos not
Cites wtknow · 2023-10 · Physics Stack Exchange · on “Conservation of Angular Momentum, why does person rotate only one way?”
As seen from the video that i linked, when the wheel is spinning then he doesnt rotate, but as soon as he flips the wheel he will start to rotate. Why he doesn't rotate both counter and anticlock wise? Also why does right hand rule apply to this? Video: [this video]