[煎蛋小學堂]倒車爲何那麽難?

作者:admin

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2015-4-23 11:33

[煎蛋小學堂]倒車爲何那麽難?

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[煎蛋小學堂]倒車爲何那麽難?

節目簡介:

你是不是對日常生活中一些稀松平常的現象産生過好奇心?

到底爲什麽會是醬紫的呢?

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還在等什麽,一起來一場對未知世界的奇妙探索之旅吧~~

參考雙語文本:

When you turn a car's steering wheel, whether you go forwards or backwards. So it seems like it should be just as easy to steer going backwards as going forwards.But clearly,it's not.Suprisingly,the difficulty of driving backwards has almost nothing to do with the direction you're facing and everything to do with the fact that you steer using the front wheels.
當你扭轉方向盤,車子都會隨相同的彎曲度運動。所以看起來倒車似乎和前進一樣簡單。但是顯然,事實並非如此。奇怪的是,倒車的困難之處在它幾乎與你對方向盤的控制無關問題在于你所控制的是車子的前輪。

When driving forwards,a car goes in the direction the front wheels are pointed.And when driving backwards,the car goes where the back wheels are pointed.Simple!But the difference is that going forwards,the direction of travel is determined by the same wheels you steer with,so you just point them where you want to go,and that's where you go,the back wheels follow automatically.
向前行駛時,車子順著前輪的方向前行。而倒車時,車子順應的是後輪的方向。很簡單,問題在于,前進時決定方向的車輪與你控制的車輪相同,所以你只要打好方向盤車子就朝你預期的方向前進了,後輪會跟著前輪前進。

In physics,we call this a "stable"system.like dangling a pencil from your fingers-move your hand around and the pencil follows,no thought required.However,when driving backwards,the direction of travel is determined by the back wheels but you steer with the front wheels.
在物理中,我們稱之爲“穩定“系統,就像挂在指尖的鉛筆移動手指它就會跟著動,無需自具想法。但是,在倒車時,決定車子運動方向的是後輪,而你控制的卻是前輪。



So rather than just pointing the front wheels where you want to go,you have to point them in the direction that will get the back wheelsto point in the direction you want to go-it's an additional level of separation before the car does what you want.
與只需控制前輪運動不同,你需要通過控制前輪引導後輪向著你預期的方向運動。這是控制好車子的附加操作。

And in fact,if you don't make any corrections,then over time the back wheels point farther and farther away from the direction you want to go:instead of following the front wheels,they want to run away!This is an unstable system,like trying to balance a pencil on your fingertip.It's incredibly finicky and requires a ton of coordinated hand-eye feedback to maintain.
事实上,如果你不采取修正措施,随着时间流失,后轮就会越来越偏离你预期的方向:不但不随前轮运动 而且还会失控!这是一个不稳定系统,就像尝试平衡立在指尖上的铅笔一样。这相当讲究,需要不停的进行手眼反馈协调来完成。

That's why you constantly have to readjust your steering when driving backwards-mathematically,your car is like an upside-down pencil! Of course,there are some successful rear-steering wheeled vehicles-forklifts,for example,only drive slowly and choose rear-steering for greater control of their forks.
这就是倒车时你需要不断调整轮胎方向的原因-数学说法就是 你的车就像东歪西倒的铅笔!当然 也有一些很棒的后轮控制转向的车子-例如,叉车,行驶缓慢 并且选择后轮主控叉子。

But let's go in the other direction and add a TRAILER to your car steering backwards has gained ANOTHER level of difficulty:you use your front wheels to get the back wheels to point in the direction needed to get the TRAILER to point in the direction you want to go.Not complicated enough?It becomes worse the more trailers you add each one adds another level of separation between the direction of your steering and the actual direction of travel.
現在我們加點難度,給車子加個拖車,這下倒車難度又更上一層樓了:你通過控制前輪引導後輪的方向,同時還需要使拖車向預定方向運動。難度還不夠?增加更多拖車後情況就更糟糕了,每增加一輛拖車就會使實際運動方向更加偏離預期的運動方向。

Which is why it's nearly impossible to push on one end of a chain or a rope and have the other end go where you want it to,and why you will never,ever blance a flexible rope or chain upright on your finger.which makes backwards driving seem downright easy!
這就是爲何將鏈條或繩索的一端置于指尖時你永遠無法控制另一端的運動方向,也是你爲何永遠無法令靈活的鎖鏈直立于指尖上的原因。相比之下,倒車真是簡單爆了!