字幕表 動画を再生する 英語字幕をプリント Last week, a senior vice president of Google quietly parachuted from 135,890 feet, breaking the sound barrier in the process. How is it that a human can fall faster than sound? Hey guys, Amy here for DNews, and to call the sound barrier a “barrier” is actually a bit of a misnomer. Anything moving through the air, like an airplane, has to push air molecules out of its way to move. This forms a pressure wave in front of and behind the airplane, and the faster that airplane flies the faster those molecules have to move out of the way. The pressure waves start to compress. At a certain point, the molecules can’t get out the way fast enough and. They form a “barrier” in front of the airplane that also compresses the pressure wave into a single shock wave that moves at the speed of sound, commonly called Mach 1. When the airplane goes faster than the speed of sound it pierces through that barrier created by the built up shock wave, creating a negative pressure space around it. The sonic boom is the sound associated with the sudden change of pressure. Engineers worked long and hard to get a plane to fly through the so-called sound barrier and go supersonic in level flight in the 1940s; for years pilots trying to fly faster than sound had airplane shake and break apart around them thanks to those pressure waves. It was Chuck Yeager piloting the X-1, which was designed to look and fly like a bullet, who first broke through that invisible wall in the sky. So how can a human make it through the sound barrier without a perfectly aerodynamic rocket-powered airplane? There’s more to going supersonic than just speed. Altitude, and specifically the thickness of the atmosphere at different altitudes, is a major factor. The higher the altitude the thinner the atmosphere, which means there are fewer air molecules for a plane, or a body, to get out of the way. Because extreme parachute jumpers like Felix Baumgartner and Alan Eustace jumped and free fell from such high altitudes, it was easier for them to move air molecules out of the way to hit Mach 1 because the air is less dense. Baumgartner didn’t need rockets to break through the sound barrier falling from more than 127,000 feet. Yeager, flying the X-1 at 43,000 feet, on the other hand, did need a rocket boost. But interestingly, Baumgartner’s supersonic moment required just 10 miles per hour less than Yeager’s. And, of course, specialized pressure suits these jumpers wore play a big part. Suits designed to protect the wearer from the shock waves associated with the sound barrier, even in less dense air, are vital to success. And not to mention survival. So what do you guys think. Would you make a supersonic jump? Let us know in the comments below and don’t forget to subscribe for more DNews every day of the week.
B1 中級 あなたは音の壁を破って生き残ることができますか? (Can You Survive Breaking The Sound Barrier?) 118 10 Jack に公開 2021 年 01 月 14 日 シェア シェア 保存 報告 動画の中の単語