
This one is for Ben or maybe Charlie. Let's say I'm standing on a skateboard. I don't roll even though the earth is rotating. How fast would the earth have to rotate beneath me to make me roll relative to "stationary" objects around me, like trees?
Ben wrote a blog post after stumbling through it on the show. Here it is! http://paleocave.sciencesortof.com/2010/07/homework/
