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Name: AP Physics C: Rotational Dynamics Review - 2 of 2 (Mechanics) Category: Rotational Motion Date Added: 2017-04-28 Submitter: Flipping Physics Calculus based review of the cross product torque equation, how to do a unit vector cross product problem, rotational equilibrium, the rotational form of Newton’s second law, the angular momentum of a particle and of a rigid object with shape, the derivation of conservation of angular momentum, and a conservation of angular momentum example problem which reviews a lot of the pieces necessary to understand conservation of angular momentum. For the calculus based AP Physics C mechanics exam. Want Lecture Notes? Content Times: 0:15 The cross product torque equation 1:10 Unit vector cross product example problem 3:32 Rotational equilibrium definition 4:55 Rotational form of Newton’s second law 5:37 Angular momentum of a particle 7:08 Angular momentum of a rigid object with shape 7:49 Conservation of angular momentum derivation 8:57 Conservation of angular momentum example problem 10:57 Visualizing the problem 12:04 The conservation of angular momentum equation 12:54 Solving for the constant value of the variable y. 14:04 Substituting in known values 15:38 Does our variable answer make sense? Multilingual? Please help translate Flipping Physics videos! AP Physics C Review Website Next Video: AP Physics C: Rotational vs. Linear Review (Mechanics) Previous Video: AP Physics C: Rotational Dynamics Review - 1 of 2 (Mechanics) Please support me on Patreon! Thank you to Sawdog for being my Quality Control individual for this video. AP Physics C: Rotational Dynamics Review - 2 of 2 (Mechanics)

Name: AP Physics 1 - Angular Momentum Category: Rotational Motion Date Added: 2015-11-19 Submitter: FizziksGuy Brief introduction to angular momentum for algebra-based physics courses such as AP Physics 1. AP Physics 1 - Angular Momentum

Name: Dancing T-Handle in Zero-G Category: Rotational Motion Date Added: 2015-08-26 Submitter: FizziksGuy HD video of the installation handle on Space-DRUMS in free floating rotation showing a bi-stable state due to intermediate moments of inertia. Dancing T-Handle in Zero-G

So here's something neat that I just stumbled across on YouTube. It also connects to our current unit of rotational dynamics perfectly. Its called "Cubli" which a compound of the English word 'cube' and the German word 'li' meaning something small in size. Cubli is basically a 15x15cm cube that can move and balance with the help of angular momentum. It contains three flywheels are able to achieve high angular velocity (ω) and acceleration and react quickly to external forces with the help of sensors that detect changes in inertia and then change the angular velocity of the wheels. The system is accurate enough to balance cubli on its edges and corners, and remain balanced even after being pushed. Whats more, by spinning the flywheels very fast to create angular momentum and then stopping suddenly cubli can create enough force pop itself up from laying flat to balancing on a corner. This is because of the impulse-momentum theorem which states that impulse=momentum so angular momentum=L=Iω=imulse=FΔt, so Iω=FΔt, and solving for force F=Iω/Δt. Since I (moment of inertia) is a constant, cubli is able to spin its flywheels fast enough and stop them is such little time that it is able to create enough force throw its mass onto an edge and then corner, and then react fast enough to balance. Here's a video of the cubli in action.