如图所示，轻弹簧的一端悬挂于O点，另一端与小球P相连接，将P提起使弹簧处于水平位置且无形变，然后自由释放小球，让它自由摆下，在小球摆到最低点的过程中
—What day is it tomorrow ? — .
has a “ white Christmas ” .
Ed smiles .
—Do you like winter spring ? —I like spring .
There are some and some on the farm .
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