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> 如图所示，一根轻杆两端有小球a、b，它们的质量分别是m和2m，杆可绕中心点O自由转动，使杆由水平位置无初速度释放，杆转至竖直位置的过程中（） A．b球的重力势能减少，动能增加，机械能守恒 B．杆对a球做正功 C．杆对b球做正功 D．整个系统的机械能守恒

问题：

发布时间：2024-09-11

如图所示，一根轻杆两端有小球a、b，它们的质量分别是m和2m，杆可绕中心点O自由转动，使杆由水平位置无初速度释放，杆转至竖直位置的过程中（）

A．b球的重力势能减少，动能增加，机械能守恒

B．杆对a球做正功

C．杆对b球做正功

D．整个系统的机械能守恒

参考答案：

提问用户：Fj***u2m

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