题干

两小球ABA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AB,下列说法正确的是()

A:通过最低点时小球A的机械能大于小球B的机械能

B:两小球从释放至运动到最低点的全程中机械能均守恒

C:两小球从释放至运动到最低点的过程中重力的冲量一定相等

D:小球A运动到最低点时的速率大于小球B运动到该点的速率

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D

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    A thick book of rules and guidelines tells Hollywood moviemakers how to treat animals. Karen Rosa leads the American Humane Society's film and television group. He said, “Everything from the smallest insect to the largest mammal shall be protected. We believe that for the sake of entertainment, everybody should go home alive.

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    A new film “Rise of the Planet of the Apes” tells about the creation of super intelligent apes through science. However, no real animals were among the performers. Computer generated imagery provided the chimpanzees, gorillas and orangutans that movie goers see. Clare Richardson is the president of the Diane Fossey Gorilla Fund. She says computer generated imagery should decrease the use of animals in the film industry. She praises movie makers for the use of computer-made animals.