Author Archives: Andy Rundquist

About Andy Rundquist

Professor of physics at Hamline University in St. Paul, MN

Constraint forces for path in 3D

This is a post mostly for my future self. What got me thinking about it was this comment about my planetary tunnels post: which is actually referring to a really old post of mine about how to dig a well. … Continue reading

Posted in math, mathematica | Leave a comment

Does the hoop hop?

I greatly enjoyed this recent video from StandUpMaths: The set up is a hoop with a mass attached at one point. It’s rough so it rolls without slipping. It’s released with some angular momentum with the extra mass starting at … Continue reading

Posted in general physics, math, mathematica, physics | 1 Comment

Planetary tunnel oscillators

Pick a point on the earth and start digging. It doesn’t have to be straight down. Keep it straight (careful! it’s harder than you might think) and keep going until you come back to the surface. Ok, now drop a … Continue reading

Posted in general physics, mathematica, physics, teaching | 2 Comments

Dropping ladders

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 … Continue reading

Posted in general physics, mathematica, physics, teaching | 2 Comments

Mathematica for free

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 … Continue reading

Posted in computational data science, mathematica, programming, teaching | 11 Comments

Computational Data Science capstone class

In just over a week the CDS capstone class starts and I’m not nearly ready. It’s been a while since I taught a class (Spring 2021 in the pandemic) and I’m a little rusty. But I remembered how useful it … Continue reading

Posted in computational data science, sbar, sbg, syllabus creation, teaching | 2 Comments

Rolling without slipping on curved surfaces

I’ve been trying to see if I can model balls rolling on curved surfaces and I think I’ve cracked it. Here’s a teaser to get you interested: What you see is a sphere rolling on a curved surface. The blue … Continue reading

Posted in fun, general physics, mathematica, physics | Leave a comment

Situations that share equations of motion

Recently my friend Rhett Allain has been making some awesome videos showing how to solve complex problems with a Lagrangian approach. I love it when he posts a new video because it usually motivates me to try to model something … Continue reading

Posted in mathematica, physics | 3 Comments

Rigid bodies, formulation and examples

My friend Rhett Allain gave me a good challenge recently with this tweet: 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 … Continue reading

Posted in mathematica, physics, syllabus creation, teaching, twitter | 1 Comment

Creating bike routes with python

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” … Continue reading

Posted in fun, math, programming, technology | Leave a comment