There's a tale we've all heard: A penny dropped from the top of the Empire State Building would fall at such a rate it would impale and kill anyone it hit down below.
The myth somehow weaseled its way through the generations, horrifying elementary school students and causing reasonable people to wonder if a day of New York City sightseeing would be their last.
But quietly, about a decade ago, University of Virginia physics professor Louis Bloomfield put those fears to rest by happily getting pelted with pennies from high above. He answered the question and lived to tell about it.
Bloomfield hosted his experiment in a park in Charlottesville, Virginia. There he launched a helium balloon carrying pennies hundreds of feet in the air and, using radio-control airplane parts, devised a way to drop the pennies to the ground.
On the ground, Bloomfield tried his best to catch the falling coins.
"The pennies didn't hurt," he said. "They bounced off me and it felt like getting hit by bugs, big raindrops, or little hail pellets. No bruises, no injuries. I was laughing the whole time."
He found pennies fell less like bullets and more like leaves, fluttering to the ground at a measly 25 mph. The reason: They're aerodynamically unstable, the air pushes up on them, halting their acceleration. It's something called relative wind, similar to that experienced by skydivers.
"The air exerts upward forces on fallen objects and it prevents them from falling faster and faster," he said. "Not because they're moving, but because they're moving through the air."
For a penny to plummet at a lethal rate, it would need to fall in an airless environment. Bloomfield said a penny, or anything else, would hit the ground at a speed of about 210 mph if it were tossed from the Empire State Building in an airless environment. At that speed, Bloomfield said, anything, even a piece of paper, is dangerous. Bloomfield said a penny at 210 mph could break your skin if it hit you on its edge.
Items that are more aerodynamic or heavy, such as a ball point pen or bowling ball, may be able to cut through the air better. Both items, Bloomfield said, if dropped from the Empire State Building, would hit the ground at close to 210 mph.
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