Рет қаралды 73,114
DENJIRO: Today, I’m going to give you a quiz by performing an experiment with pendulums. Here, I have two balls of the same size suspended by string. Let me move one of the balls. As you can see, they repeat the same movement.
Now, here’s a quiz about collision. I’ve changed one of the balls to one that is smaller and lighter. If I strike the small ball against the big ball, will the movement be the same as before?
GIRL: Of course not.
DENJIRO: Let me give it a try. It’s moving differently from before. But if you look closely, it’s repeating the same pattern. Here’s another quiz. Now, what if I strike the big ball against the small ball? How will they move?
GIRL: I don’t know.
DENJIRO: Again, they move differently. But if you look closely, once again, they are repeating the same pattern. Even if you strike the small ball against the big ball or vice versa, it returns to the original position after two collisions. Let me explain what’s going on by taking a look at what happened when I struck the small ball against the big ball.
After the first time the small ball collides against the big ball, they both move away from each other. They then collide at the same point again. The speeds at which the balls move away from each other and when they collide again are the same. But the directions the balls move in are the opposite. Therefore, the pendulums returned to the original position after two collisions. The same happens when the big ball is struck is against the small ball. It returns to the original position after two collisions.
I hope energy will bring you all happiness. Our magic word is "Happy Energy!"