POWER(linear): Units 10 & 11 Dr John P. Cise, Professor of Physics, Austin Community College, 1212 Rio Grande St., Austin Tx. 78701 [email protected] & NY Times May 17, 2015 by John Branch Dean Potter, Extreme Climber, Dies in Base-Jumping Accident at Yosemite Dean Potter, one of the generation’s top rock climbers and charismatic personalities, was one of two men killed in a BASE-jumping accident at Yosemite National Park in California on Saturday. Potter, 43, and the other man, Graham Hunt, 29, leapt near dusk off Taft Point, a promontory about 3,000 feet above the floor of Yosemite Valley, not far from the iconic granite masses of El Capitan and Half Dome. Flying in wingsuits, they tried to clear a notch in the granite cliffs but instead smashed into the rocks in quick succession. “It’s tremendously sad,” said Gauthier, an occasional climbing partner of Potter, who lived in Yosemite. “Dean was part of this community and had such an impact on climbing. He was a luminary and in the pantheon of climbing gods.” INTRODUCTION: Half Dome mountain at left in Yosemite National Park is 4800 feet from valley floor to summit. QUESTION: (a) How much gravitational potential energy did Dean Potter gain in climbing Half Dome? Do in English system (b) How much work did he do during this 4800 ft. climb? (c) Convert 1 hr + 19 min. to seconds? (d) How powerful was Dean during the climb? (in units of ft. lb./s) . (e) Find his Dean Potter was one of two men killed while BASE jumping in Yosemite National Park. power in units of horse power? Sinewy and strong at 6 feet 5 inches and (((180 pounds))), with dark hair often at shoulder length, Potter stood out for his looks and audacious achievements. He was a proselytizer for climbing, BASE jumping and living free. “Part of me says it’s kind of crazy to think you can fly your human body,” Potter told The New York Times in 2008. “Another part of me thinks all of us have had the dream that we can fly. Why not chase after it? Maybe it brings you to some other tangent. Chasing after the unattainable is the fun part.” Potter, who grew up mostly in New Hampshire, bloomed on the Yosemite climbing scene nearly 20 years ago. In 2001, he climbed the nose route of El Capitan in a record 3 hours 24 minutes. He was the first to free-climb (no ropes except to catch falls) both El Capitan and Half Dome in 24 hours. In 2008, he was featured in The Times for highlining, essentially extreme tightrope-walking between cliffs. He spent much of his time in recent years BASE jumping and wingsuit flying. This month, (((Potter made it to the top of Yosemite’s Half Dome in 1:19,))) and he completed the round trip in under 2:18, considered a record. “Dean Potter has been a visionary influence in climbing for 20 years,” said Alex Honnold, another of the world’s best-known rock climbers and a Yosemite resident. HINTS: Power(P) = Work(W)/Time(t) = W/t , W = ΔK + ΔU , U = mgh , mg = weight , g = 32 ft./s2 , 3600 s./hr. ,60 s./min. , 550 ft. lb./s. = 1 horsepower = 1 HP. ANSWERS: (a) 864,000 ft. lb. , (b) ~ 864,000 ft. lb. , (c) ~ 4740 s, (d) ~ 182.3 ft. lb./s , (e) ~ 0.33 HP NOTE: If you Google human horsepower you will find healthy athlete does on average generate ~ 0.3 - .4 HP .