Placeholder Image

字幕表 動画を再生する

  • When you turn a car’s steering wheel, the car follows a path along the same curve regardless

  • 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

  • youre facing and everything to do with the fact that you steer using the front wheels.

  • 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. In physics, we call this a “stablesystem, like dangling

  • a pencil from your fingersmove 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. 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 wheels

  • to point in the direction you want to goit’s an additional level of separation before the

  • car does what you want. 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. That’s why

  • you constantly have to readjust your steering when driving backwardsmathematically,

  • your car is like an upside-down pencil!

  • Of course, there are some successful rear-steering wheeled vehiclesforklifts, for example,

  • drive only slowly and choose rear-steering for greater control of their forks.

  • But let’s go in the other direction and add a TRAILER to your carsteering 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 addeach one

  • adds another level of separation between the direction of your steering and the actual

  • direction of travel. 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 balance

  • a flexible rope or chain upright on your finger. Makes backwards driving seem downright easy!

When you turn a car’s steering wheel, the car follows a path along the same curve regardless

字幕と単語

ワンタップで英和辞典検索 単語をクリックすると、意味が表示されます

B1 中級

なぜ逆走しにくいのか? (Why is it Harder to Drive Backwards?)

  • 608 32
    Ashley Chen に公開 2021 年 01 月 14 日
動画の中の単語