WEST MIFFLIN - The October issue of The Journal of Applied Physics will feature a Pittsburgh professor and Pittsburgh's favorite amusement park.
Dr. Jack Dammer, who has a joint appointment at both Carnegie Mellon and Kennywood, had a "eureka" moment when he saw a Kennywood gardener crawl under a bench to retrieve a penny. "I realized there were so many forces at work in found money in parks," he said. "I started making notes right away."
Dammer identified three different physical forces at work for losing money. The most common, he says, is gravity. "Money just falls off of people. Look under any bench or food area. Usually it's the lighter-weight coins like pennies and dimes, but hey - money's money."
The second force occurs only in the early-morning hours. "There's no special physics behind it, though. It's just the time they wash down the park with high-pressure hoses. The pounds of water pressure overcome the friction with the ground, and the coins gain kinetic energy. That gets converted back into potential energy when they hit curbs or trash cans. So I always check around the edges as soon as the hose guys finish a section of the park."
But the most lucrative area is around the park's famous roller coasters. "People think they've safely secured their items, but they just don't realize the centrifugal forces on them," he said. "Or is it centripetal? I can never keep those straight. At any rate, I 'did the math' on the forces and the mass of each coin, and it creates a graph of exactly where the coins are most likely to fall onto the ground. I'm getting a couple of bucks every single day."
Journal editor Sheldon Hofstetter praised Dammer's column. "The most elegant ideas often come from simple observations," he said. "Dr. Dammer has discovered an important aspect of our world. Other scientists can build on this theory -- and I suspect you're going to find a lot more physicists in American amusement parks next season, and they're all going to be trolling for cash."
