The Golf Ball Paradox

Summary by Krater

Steve Mould investigates why a golf ball thrown into a vertical cylinder pops back out again, exploring the mathematics of rolling reference frames, moments of inertia, and gyroscopic effects.

From the video

Answers: Why does a golf ball pop back out of a vertical cylinder?

• golf ball in cylinder paradox
• rotating reference frames
• moment of inertia of spheres
• gyroscopic effects on rolling balls
• motion amplification cameras

What it concludes

• The ratio of vertical oscillations to cylinder turns for a solid ball is the square root of 7 divided by 2.
• For a hollow ball, the ratio is the square root of 5 divided by 2.
• Squash balls have a higher ratio than the square root of 5 divided by 2 because their walls are thick.
• Golf balls have a higher ratio than the square root of 7 divided by 2 because their mass is concentrated towards the center.
• A gyroscopic effect causes the axis of rotation of the ball to tilt when rolling around the cylinder.