A project you can do to help slow the pandemic. Instructable or Project Guide
FearOfPhysics.com: The Basic Interactions

Rolling Wheels

Two wheels are rolling and moving toward the right at the same speed without slipping or skidding. The top wheel is larger than the bottom wheel. The rolling action is purposely hidden by the uniform red color of each, but here's the question: how does the spin speed of each wheel compare?

bigger wheel spins faster/smaller wheel spins slower
both wheels spin at the same speed
bigger wheel spins slower/smaller wheel spins faster