两小球A和B，A球系在一根长为L的轻质细绳OA上，B球系在轻质橡皮绳OB上，现将两球都拉到如图所示的水平位置上，让两绳均拉直（此时橡皮绳为原长），然后无初速释放．不计空气阻力，当两球通过最低点时，橡皮绳与细绳等长．关于小球A和B，下列说法正确的是（）

阅读短文，判断句子正（正确）误（错误）。

    On Sunday morning, Mr. Baker takes Mike and John to a plane. He opens the door of the plane and lets the children in. Soon the plane begins to up. John looks out of the window, “Oh, we're like birds in the sky!” He says. He looks at the houses, but they are like toy houses. Mike looks out of the window, too. He sees some buses. They look like toy buses. The people on the ground look very, very small, too. Then the plane comes down and down, and stops on the ground. Mike and John are very happy.

   Ruby, the artist, is an Asian elephant, She is17 years old. She lives in the zoo. Ruby has produced about 100 paintings since last year. She has made more than $ 40,000 for the zoo. Zoo leaders say Ruby first showed the talent (才能) about four years ago. Zoo workers watched her make the marks in the sand with her trunk. She rubbed (擦掉) out the marks, then made the new ones. The zoo worker gave her brushes and paints. Soon Ruby painted pictures.
   Newspaper reporters wrote Ruby, then people asked about buying her pictures. And in this way, she made a lot of money for the zoo. This is how Ruby does the paintings. A zoo worker holds different color paints. Ruby touches the colors she wants. Then the worker gives her brushes with the chosen colors in her trunk and Ruby begins painting.