问题
选择题
两个完全相同的质量均为m的滑块A和B，放在光滑水平面上，滑块A与轻质弹簧相连，弹簧另一端固定在墙上。滑块B以v0的速度向滑块A运动，如图所示，两滑块相碰后一起运动不再分开，下述正确的是k*
A．弹簧最大弹性势能为
B．弹簧最大弹性势能为
C．两滑块相碰后一起运动过程中，系统动量守恒
D．两滑块（包括弹簧）相碰后一起运动过程中，系统机械能守恒
答案
BD
搜题请搜索小程序“爱下问搜题”
两个完全相同的质量均为m的滑块A和B，放在光滑水平面上，滑块A与轻质弹簧相连，弹簧另一端固定在墙上。滑块B以v0的速度向滑块A运动，如图所示，两滑块相碰后一起运动不再分开，下述正确的是k*
A．弹簧最大弹性势能为
B．弹簧最大弹性势能为
C．两滑块相碰后一起运动过程中，系统动量守恒
D．两滑块（包括弹簧）相碰后一起运动过程中，系统机械能守恒
BD
| 完形填空。 | ||||
| It was getting dark. Some children and two Canadian women were still 1 on the ice near a big hotel. They were having a good time. Suddenly the ice 2 , and one of the boys fell into the water. The children shouted "Help, Help" They didn't know 3 to do. The two Canadian women heard 4 and skated over to get the boy out of the water. The ice was 5 , the two Canadians fell into the water, too. But they tried their best to 6 the little boy. They knew they must be 7 . If they didn't push him up onto the ice, he would soon die. Many people ran over to 8 . Some of them had ropes and poles. A young man jumped into the water to save the 9 people. The boy and the two Canadians women were out of water at last. One of the women didn't feel well. She was sent to the 10 at once. But she felt very happy because the boy was safe. | ||||
|