20、 Obama
B1 中級 米 25 タグ追加 保存
このエントリーをはてなブックマークに追加
動画の字幕をクリックしてすぐ単語の意味を調べられます！
単語帳読み込み中…
字幕の修正報告
How Does a Bicycle Stay Upright?
If you get on a bicycle and start pedalling, what do you feel?
You will feel the movement of the bicycle, as you move forward.
Doesn't it fill you with surprise that you can move forward on two wheels, just by pedalling
your way?
Let's see what happens when a stationary bicycle is pushed without a rider.
Oh, look!
The pushed bicycle keeps moving.
It's becoming slower and now it has fallen!
Oh!
No!
A moving bicycle will continue to stay upright and move forward because of momentum, till
it falls down because of gravity.
Did you know that till a few decades back, scientists thought a bicycle stays upright
because of the Gyroscopic Effect.
The Gyroscopic Effect means that a spinning wheel tends to stay aligned in its original
direction, during momentum.
This is known as Angular Momentum or spinning action.
So, if it is not the Gyroscopic Effect, what actually keeps the bicycle upright?
The scientists who study bicycles, experimented a bit more to discover, that if the gyroscopic
effect were to be cancelled, the bicycle would continue to be upright!
So, they assumed, it must be the caster effect of the wheels.
Because the bicycle wheels are attached to a centre axis on a frame to help them rotate.
What is the caster effect's role in keeping bicycles upright?
If you look at a bicycle, you will see that it is designed in such a way, that the front
wheel's steering axis makes the front wheel move faster than the back wheel.
So, when the bicycle starts moving to the left, the Centrifugal Force of the back wheel
would keep it in check, because it is still moving straight.
The wheel would automatically snap the bike to the right and keep it upright!
So, now you know, that Angular Momentum and Centrifugal Force keeps a bicycle upright
when it is moving.
コツ：単語をクリックしてすぐ意味を調べられます！

読み込み中…

B1 中級 米

How does a bicycle stay upright? Curious Questions with Answers | Educational Videos by Mocomi Kids

25 タグ追加 保存
このエントリーをはてなブックマークに追加
ally.chang 2020 年 3 月 11 日 に公開

お気に入り

loading

コメント

読み込み中…
お勧め動画

  1. 1. クリック一つで単語を検索

    右側のスプリクトの単語をクリックするだけで即座に意味が検索できます。

  2. 2. リピート機能

    クリックするだけで同じフレーズを何回もリピート可能！

  3. 3. ショートカット

    キーボードショートカットを使うことによって勉強の効率を上げることが出来ます。

  4. 4. 字幕の表示/非表示

    日・英のボタンをクリックすることで自由に字幕のオンオフを切り替えられます。

  5. 5. 動画をブログ等でシェア

    コードを貼り付けてVoiceTubeの動画再生プレーヤーをブログ等でシェアすることが出来ます！

  6. 6. 全画面再生

    左側の矢印をクリックすることで全画面で再生できるようになります。

  1. クイズ付き動画

    リスニングクイズに挑戦！

  1. クリックしてメモを表示

  1. UrbanDictionary 俚語字典整合查詢。一般字典查詢不到你滿意的解譯，不妨使用「俚語字典」，或許會讓你有滿意的答案喔