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So you're in an elevator, just scrolling through your text messages as it zooms past the 15th floor.
当电梯飞速穿过第15楼，此刻你正在 电梯内翻阅消息。
And then, suddenly, the elevator stops.
突然间，电梯停了。
That's when you realize that you're suspended in midair, and you're /really/ high up.
这时你意识到自己悬在了半空中，而且真的很高。
Maybe that's when you start to wonder: could your elevator start plummeting to the ground at any second now?
或许就在那一瞬，你在猜想电梯可能会随时 急降到地面吧？
And if it falls, could you survive it? The good news is that the elevator almost definitely won't fall.
如果电梯跌落了，你会存活吗？ 好消息是，电梯几乎可确保不会骤降
There are lots of safety features designed to prevent a plunge, including multiple ropes and brakes.
（电梯内）有包括并联绳索和急刹装置在内的许多安全设施，用于阻止骤降
And if absolutely everything fails, then there are ways to minimize the damage
若所有装置都停止工作了，也可通过将伤亡影响分散至全身这一方法
by distributing the impact all across your body.
将伤害降至最小。
But there's no guarantee that you'd survive.
但可不保证你会幸存哦。
In buildings of more than a few floors, the elevators are usually traction elevators.
在楼层不少的建筑里，电梯通常设为曳引电梯。
These work by attaching the car to metal ropes or belts and threading them through a motor,
通过将吊舱附着于金属绳或金属带上，借助电缆另一段的配重
with counterweights on the other end of the cable.
机器得以线式穿过马达。
When the motor is active, it slowly threads cable through, moving the car up or down.
当引擎运动时，它缓慢牵引着电缆，带动吊舱或上或下地移动。
If something goes wrong with the motor, the brakes stop the car.
如果马达出了问题，制动器会阻滞住吊舱。
There are different kinds of brakes, but two common brakes are found in the motor and under the car.
制动器有很多种，但在马达吊舱内常见的也就 两种。
The brakes in the motor will make the cables jam and stop as soon as the power goes off.
一旦电力用尽，引擎中的制动器就会阻塞电缆。
Meanwhile, the brakes under the car are usually designed to detect if the car's moving too fast.
同时，吊舱中的制动器也被用于侦查吊舱是否移动得 太快。
If it is, the brakes release a metal wedge into the rails along the elevator shaft.
若是太快了，制动器会沿着电梯轴释放金属楔子进入轨道。
The friction between the wedge and the rail is strong enough to slow the car down and eventually make it stop.
楔子与轨道间的摩擦强大到足以慢慢将吊舱减速 并最终使其停下。
So if the motor suddenly stopped working, the brakes would suddenly /start/ working.
所以若马达突然停止工作，制动器将立即开始工作。
It's incredibly unlikely that both the motor /and/ all the brakes would fail.
难以想象所有马达和制动器都停止工作。
But if they did, that's when the counterweights would come into play.
但若真停止工作了，那配重器可就派上用场了。
The counterweights are on the other side of the metal cable,
配重位于金属电缆的另一端，
and they're normally about the weight of the elevator car when it's half full.
大约等于电梯吊舱半满时的重量。
In the best case scenario, you'd have the right number of people in the elevator
最棒的假设情况是，电梯里的人数刚好
so that it exactly balances the counterweight -- so if you're really lucky, you might not move at all.
与配重相平衡。所以若是你足够幸运，你可能 完全没感到位移。
And if you're alone in the elevator, you might actually be lighter than the counterweights,
所以若你单独在电梯里，你当然比配重要轻，
and start moving upward — though that can still be dangerous
会开始向上移动，当吊舱冲入电梯车厢顶部时
if the car is moving too fast when it crashes into the top of the elevator shaft.
若它移动太快，那仍然是危险的。
If it's a full car, you'll probably be heavier than the counterweights, and start moving down.
若是吊舱太满，它又会比配重更重，就会开始向下移动。
In either situation, the counterweights balance out some of the acceleration from gravity.
在任一情况下，配重都会平衡一些来自重力的加速度。
By the time you reach the top or bottom of the elevator shaft, you won't be moving as fast as you would otherwise.
然而当你到达电梯顶端或底部时，你就不会移动得 那么快了。
But a lot of the time you can still expect a pretty dangerous drop --
但很多时候你依然能预想出相当危险的跌落，
especially if you're a long way from the end of the elevator shaft.
尤其是当你离电梯车厢尽头还很远时。
There's also the possibility that the brakes fail /and/ the cables snap,
也有可能是制动器罢工了，电缆崩塌了，
but there are hardly any known cases of that happening.
但那种情况几乎从未发生过。
Most elevators have multiple cables, and every single cable is designed to be able to hold the weight of a full car.
多数电梯有很多电缆，每一根都设计得 足以支撑整个吊舱的重量。
In fact, it's pretty common for elevators to have up to /eight/ cables, and with a safety factor of 12 --
事实上，通常都电梯拥有接近八根电缆，以及"12安全因素"原则，
meaning that all the cables together can hold a weight equivalent to 12 times the weight of a fully-loaded car.
就是说所有电缆加一起能承受住 12倍于满载吊舱的重量。
So even if a cable /did/ break, you'd have others holding you up.
所以即使一个电缆坏了，还有其他电缆能支撑住你。
There's one famous case where an elevator's brakes failed and its cables snapped —
在一个著名的案例中，一电梯的制动器坏了，电缆也崩塌了
it happened in 1945, when a pilot accidentally crashed his plane into the Empire State Building.
这发生在1945年，一个飞行员无意将飞机在帝州建筑物内撞毁。
A woman named Betty Lou Oliver was told to get in an elevator to get out of the building.
据说一位名为贝蒂娄欧莉瓦的女士为出大楼进入了电梯。
But the cables were weakened by fire, and they snapped.
但电缆因火损伤并崩塌了。
Oliver and the car fell over 75 stories to the basement. And ... Oliver survived.
欧莉瓦和吊舱跌落了至少75层，直达地下室。并且……欧莉瓦幸免于难。
It's not clear exactly /how/ she survived, but one possibility is that the car was moving so fast
并不明确她是如何存活的，但一个可能性是吊舱移动得太快
that it compressed the air below to the point where it actually cushioned her fall.
以至于吊舱刚好压迫下层空气到 能缓冲她跌落冲力的程度。
Another possible explanation is that all the broken cables piled up at the bottom of the shaft and softened the impact.
另一可能的解释是所有损坏的电缆堆积在轴的底层 以此减轻了冲击力。
Whatever happened, the elevator basically had a built-in safety net.
不管发生了什么，电梯基本上有套完善的安全网。
But back to your stuck elevator on the 15th floor.
但回到你困于15层的话题上来，
You're still worried that it might fall, even though you know that's super unlikely.
你还是担心它可能会跌落，即使你明知那不太可能。
If it does, you might've heard that you're more likely to survive if you jump just before you hit the ground.
若确实如此，你可能曾听说，如果你在着地前跳起，你就很可能存活。
But there are two main problems with that idea.
但那个说法存在两个主要的问题
First, the timing has to be absolutely perfect, so that you're jumping /exactly/ when the car hits the ground.
首先，时机必须恰到好处，那样你才可以精准地在吊舱着地时起跳。
And second, you'd need to have an exceptionally strong jump.
其次，你需要有超强的跳跃力。
Chances are you're moving really, really, fast, and your jump won't be powerful enough
风险在于你动的真的很快，且你的跳跃没强大到
to make a difference in your speed when you hit the ground.
使落地时你的速度与不跳时有明显区别。
So a more realistic option might be to lay your body against the floor. Even that can be tricky.
所以一个更可行的选择可能是将身体靠近地板。那看起来甚至有些费事
If the ropes are broken and you're in free fall,
若绳索坏了且你在自由坠落，
you'll feel weightless and it'll be hard to pull yourself to the floor.
你会有无重力感 此时将自己拖到地板处是有些困难。
But if you manage to do that, then the impact will be distributed more evenly across your body.
但你若成功了，冲击力会更平均地 分配到身体各部。
It's not a guarantee you'll survive, but it might be your best shot.
这并不保证你会存活，但它可能是你最棒的一博。
Thanks for watching this episode of SciShow, which was brought to you by our patrons on Patreon.
感谢您观看这段科学秀，由我们的赞助商通过 Patreon为您带来
If you want to help support this show, just go to patreon.com/scishow.
若你想赞助支持这一节目，敬请登录patreon.com/scishow
And don't forget to go to youtube.com/scishow and subscribe!
也别忘了上youtube.com/scishow订阅我们的节目哦！
