GeekDad Puzzle of the Week: Roller Coaster Thought Experiment

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“Perhaps this wasn’t the best idea.” (My thought from back seat of Ghostrider with 6yo Leif.) Image: Flickr/RollerCoasterPhilosophy

Last week the offspring and I tagged along with my wife to a conference in California. She was presenting the results of her PhD dissertation research with mothers of chronically ill children. The kids and I went to the beach. I believe we may have had more fun than Kristi. We also went to Knott’s Berry Farm, where Leif — now 48 1/4 inches tall — was just tall enough for the radical roller coasters. There were absolutely no lines and so Leif and I strolled through the gates and directly onto Ghostrider, where we seated ourselves in the last seat of the last car. With my continued assurances of a fairly mellow ride, we clicked toward the top of the first hill. And long before we crested, Leif and I were whipped over the top and down many hundreds of feet toward the cold, hard ground, pulled over by the gravity already working on the front seats. I had a couple thoughts. Here they are in no particular order:

• “I’m going to die in an immediate and bloody fashion.”

• “If I survive, Kristi will kill me. And then I will die slowly and painfully.”

• “There’s another quarter in the therapy jar for Leif’s midlife years.”

• “How can the back seat of a roller coaster ‘go faster’ than the front seats without the train expanding and contracting?”

It’s the final question that is the basis for this week’s GeekDad POTW. Rather than a puzzle, this is a thought experiment: How can the rear seats of a roller coaster “go faster” than the front seats, with all seats ending up in the same place, in the same order? I will accept any well-reasoned answer. Bonus entry into the hat for any answer that is both well-reasoned and also harebrained.

Submit your answers to Geekdad Central by Friday mid-morning for your chance at winning this week’s $50 ThinkGeek gift certificate!

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