Colorado State University

This week, McKenna shows us how to build Rotation Translation. In this surprising experiment, 3 balls go down 3 different tracks of varying widths. Can you guess which will get down the first?

What’s Going On?

All 3 tracks have the same slope, so it’s a questions of rotational motion versus translational motion down the track. The narrower the track, the more progress the ball makes it down the track every time it rotates. Also, if the track is very wide, the ball rotates slower. Think about what would happen if the track is as wide as the ball–it gets pinched in between the track and won’t rotate at all!