Abstract

Consider two masses resting in front of a wall in a frictionless one-dimensional world. Now set the mass furthest from the wall into motion (constant speed). Count the collisions mass-mass and mass-wall until the state of the system becomes stationary. Increase the mass ratio by powers of 100, repeat the experiment and be amazed! To celebrate Pi Day 2019 I am going to present a surprising fact of trivia about the number $\pi$. This is not a research talk and requires only some knowledge of basic geometric and physical facts. I was made aware of this by a wonderful youtube video by 3blue1brown, who posed this as a riddle in January. To avoid spoilers, maybe refrain from watching the solution video before the talk.