Simulation and experimental evidence for 2021 AP Physics 1 problem 4 - block and cylinder on incline

About half of the videos in my 2020 AP Live series discuss released AP Physics 1 free response problems, including experimental evidence for the solutions.  I use these videos regularly during exam review time: students solve a problem, then if they don't do well, they are tasked with watching the corresponding video.  

I need to start updating with experiments covering the released problems since 2020.  And here's that start.

Last summer, my son Milo asked me to partner with him to enter a math/science video contest.*  I had been grading the paragraph-response problem, number 4 on the 2021 AP Physics 1 exam.  A student from Georgia, Widener Norris, had pointed me to the deeper meaning behind the energy bar chart for an object rolling down an incline.  Milo coded a simulation to produce energy bar charts and energy-vs.-position graphs for sliding blocks as well as rolling objects.  

* Our video earned honorable mention.

And so I did this 12 minute live show about the problem.  The show references Milo's simulation, which I highly recommend for standalone exploration about the cylinder/block situation.  You can change the incline angle, coefficient of friction, and type of object; press play, and you'll see the energy bar chart and energy-vs.-position graphs develop, frame by frame if you choose.  

The video shows, in real time and in slow motion, a block and cylinder sliding down an actual incline such that they reach the bottom with the same speed - just as the AP question postulates.  And then I discuss an unusual method of experimentally determining the rotational inertia of my pet hippopotamus Edna as she rolls gleefully down an incline.