SuperFly Physics

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At SuperFly Physics, Andy Rundquist shares ideas for teaching physics, fun science experiments, and interesting physics problems.

SuperFly Physics

3d ago

AppSheet is a google product that enables you to use Google Sheets as a backend database for a mobile app that works in both the Android and Apple ecosystems. I encourage you to check it out, as it’s become a go-to tool for me to think about interacting with students and my colleagues at my school. Quick note: it’s really designed to be used by people on the same domain (yourcoolschool.edu, for example), not really to produce a true mobile app for the world. This post is about some brainstorming I’ve been doing to think about a campus app that could be useful.
What I’ve done so far
Here’s a qu ..read more

SuperFly Physics

1y ago

This is a post mostly for my future self. What got me thinking about it was this comment about my planetary tunnels post:
Straight tunnels? What about ones using the Lagrangian drooping rope optimized as the line?
— Andrew Jagger (@ajagger01) February 27, 2023
which is actually referring to a really old post of mine about how to dig a well.
In order to add in the effects of a spinning planet, there are two or three major routes I could take:
Set the constraints on the path to be for a spinning path.
Just add the coriolis and centrifugal forces to my other calculations
Do either (1) or (2 ..read more

SuperFly Physics

1y ago

My friend Rhett Allain has really got me interested in this ladder drop posted by Veritasium:
Here’s Rhett’s awesome explanation:
Of course I wanted to see if I could model it with Mathematica, and, after finding I could run Mathematica for free on my windows laptop, I thought I’d revisit this problem, since I think I found something interesting.
Physics involved
Here’s what I did:
I modeled the rungs of the ladder as rigid sticks with a mass, a length, and moment of inertia
I modeled the ground as a one-way spring (it only pushes up if either end of the rung goes below the ground, it doesn ..read more

SuperFly Physics

1y ago

In this post I’m going to try to capture the steps I took today to get a Jupyter Notebook to run Mathematica commands. I did it on a Windows laptop so if you’re on a Mac of Linux you’ll have to make appropriate adjustments.
Why free?
Mathematica is not free. A single license can be over $1000. Student versions are more like $200 but there’s no question that it’s pricey, especially when compared with python-based computing. Of course, it definitely has value! The amount of development that’s been poured into it, including just in the last few years, is amazing. Want easy to use neural networks ..read more

SuperFly Physics

1y ago

My friend Rhett Allain gave me a good challenge recently with this tweet:
What about a bead on a freely rotating hoop that can rotate in three dimensions?
— Rhett Allain (@rjallain) November 23, 2022
I had been working on a problem that he posted about regarding a bead sliding freely on a hoop that is spinning about an axis in its plane that goes through the center. That’s a pretty typical Lagrangian Dynamics-type problem and I wondered what would happen if the hoop wasn’t driven to constantly go with a particular angular frequency but rather was set spinning on that axis with that initial ..read more

SuperFly Physics

1y ago

This weekend my goal was to ride 50 miles to and from my house. In my last post I showed four ways to find where I could get to for a certain distance, but I really hate “there and back” rides, so I wanted to find loop-based routes that would have my target distance and not have any doubling back. I used basically the same tools and I’m decently happy with the results.
tl;dr here’s the route How’d I do it?
Here’s the basic gist of what I did:
Get the lat/long of my house to have a starting point
Do some geo-based math to find points on a regular polygon that includes my house. I set the polyg ..read more

SuperFly Physics

1y ago

UPDATED WITH 4th APPROXIMATION!
Last weekend I went hammock camping by towing all my gear behind my bike. I loved it and now I’m interested in finding other adventures that won’t tax me too much. I really think that, for now, 30 miles in one day towing the trailer is a good limit for me. It leaves me enough energy to make camp and I’m able to relax and enjoy myself.
1st approximation
My first thought was to just look at a map with a 30-mile radius circle centered on my house. I figured if I could find any campgrounds in that circle I’d be good to go.
30 mile radius circle around my house
The p ..read more

SuperFly Physics

1y ago

For a long time I’ve wanted an app that could
Allow my students to take a picture of their work and share it with the class
Certainly my computer should be able to display it, but with thumbnails for all the images
Bonus if all the images are on everyone’s device
This post is about my attempt to make just such an app in Google Apps Script. It includes detailed instructions for how you can make your own copy. If you want to see it in action, see this vid.
Before jumping in, I want to say thanks to some great twitter friends who had thoughts about other ways to do this. I haven’t tried them al ..read more

SuperFly Physics

1y ago

I’m helping to run a workshop this week and we realized that instead of using post-it notes through the day to capture “burning questions” we could use a tool that both collects questions and allows the audience to vote on them.
After the first day of post-it notes I volunteered to get us set up with one of the many systems that exist that do this. I went back to my hotel room and did the usual google searching, finding tools I had used (including the one that the Physics Education Research Conference organizers used earlier this month at their opening session) and others I hadn’t heard of. Un ..read more

SuperFly Physics

2y ago

The Brachistochrone curve is the shape of a wire for beads to slide down (friction free) to get from point A to point B the fastest. Note that since I used the word “down” there I’m implying this happens in gravity. Here’s an old post of mine describing how I go about teaching it. This post is all about scratching an itch I’ve had for a while: What if instead of sliding beads we want to roll balls. Is the shape the same? Spoiler: Nope, not the same.
My first thoughts had to do with how you’d factor rolling into the typical analysis. Normally you determine the integral formula for the time to g ..read more