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Title: How to Fall 47 Stories... and Live
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Published: Dec 18, 2007
Author: http://blog.wired.com/defense/2007/12/ho
Post Date: 2007-12-18 20:33:00 by tom007
Keywords: None
Views: 322
Comments: 4
How to Fall 47 Stories... and Live By Noah Shachtman EmailDecember 17, 2007 | 9:32:02 AMCategories: Over the Top Amd_scaffoldingpolice How did Alcides Moreno, a New York City window washer, manage to fall 47 stories -- and live? His brother, Edgar, was up on the same shaky scaffold, and didn't make it. And fifty percent of people who fall a mere "four to five stories die. By the time you reach 10 or 11 stories, just about everyone dies," Dr. Sheldon Teperman tells the New York Post. So he did Moreno survive? The Post has a theory: he was able to cling "to a 1,250-pound scaffold that acted like a surfboard in the sky." Those grappling with why he miraculously survived his plunge from the roof of a 47-story high-rise say the aluminum platform added air resistance that slowed his descent - and blunted the tremendous force of hitting the concrete pavement in an alley below. Maybe, experts said, a random air current rising between the Upper East Side buildings where Moreno plummeted slowed him the extra bit that spared his life... In a free fall, both men would quickly have hit a maximum speed of 124 mph, or terminal velocity - the point when gravity pulling a person down is balanced by upward air friction, said James Kakaklios, a physics professor at the University of Minnesota. But the scaffold's platform likely slowed Alcides' descent "significantly" by pushing the air, he said. His landing position also could have made a huge difference. "If he was lying flat, not only would the scaffold act as a shock absorber, but the force to stop him would be spread more evenly over his body. If he came down on one point, the sudden shock could easily break the back or neck," Kakaklios said. Over the weekend, Moreno opened his eyes and started moving his arms and legs, his cousin said.
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#4. To: tom007 (#0)
http://answers.google.com/answers/threadview?id=124248 How high does an average limp person have to fall from to hit the ground at terminal velocity? Honestly, I'm only asking this question out of pure curiosity, and so I can point out to acrophobic friends that being on a balcony on floor x is no more life-threatening than being on a balcony at floor y. I'd like to know what the minimum value of y is for this statement to be true. ANSWER: The terminal velocity of a falling body occurs during free fall when a falling body experiences zero acceleration. The magnitude of terminal velocity depends on the weight of the falling body. For a heavy object, the terminal velocity is generally greater than a light object. This is because air resistance is proportional to the falling body's velocity squared. There is much more to determining terminal velocity than simply body posture and height. There are, however, some rough estimates that you can use in order to prove your point to your friends. It is estimated that the human body will reach 99% of terminal velocity after falling 1,880 feet (573 meters) which takes anywhere from 10-14 seconds. With normal posture and normal atmospheric pressure, this is a speed between 117 and 125 miles per hour, or approximately 54 meters per second. Another source I found stated that a human would have to fall over 400 yards (1,200 feet) prior to achieving terminal velocity. Now, a building story is approximately 12.5 feet. Using the lower number of 1,200 feet and the very basic information above, you would have to fall from approximately the 96th floor balcony to achieve terminal velocity. Now, I am sure there will be a physics genius or two that will calculate the exact distance and speed required using in depth formulas, however, I feel that the above information (and the references below) should suffice for your friends. :) Thanks for you very interesting question and I hope the above information is helpful. If you need any additional clarification, please let me know. Regards, -THV Search Strategy: terminal velocity human References: The AFU and Urban Legend Archive Death - Falling Terminal Velocity http://www.urbanlegends.com/death/falling_terminal_velocity.html Speed of a Skydiver (Terminal Velocity) http://hypertextbook.com/facts/JianHuang.shtml Ask a Scientest - Falling Bodies http://newton.dep.anl.gov/askasci/phy00/phy00012.htm Physics Forum http://www.physicsforums.com/topic.asp?TOPIC_ID=7318
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