如图甲所示，劲度系数为k的轻弹簧竖直放置，下端固定在水平地面上，一质量为m的小球

发布时间：2017-05-19 14:08 │ 来源：www.tikuol.com

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问题：

如图甲所示，劲度系数为k的轻弹簧竖直放置，下端固定在水平地面上，一质量为m的小球，从离弹簧上端高h处自由下落，接触弹簧后继续向下运动。若以小球开始下落的位置为原点，沿竖直向下建立一坐标轴0X，小球的速度v随时间t变化的图象如图乙所示。其中OA段为直线，AB段是与OA相切于A点的曲线，BC是平滑的曲线，则下列判断正确的是

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A．对应于图乙A点，，小球所受重力的瞬时功率最大

B．对应于图乙B点，，小球的加速度a=0

C．对应于图乙C点：，弹簧的弹性势能最大

D．小球从A到C的过程中，重力做的功大于弹簧的弹性势能的增量

考点：v-t图像平均功率和瞬时功率的区别弹性势能

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E. Where have you been?
F. It's reported that it has changed a lot.
G. We'll see a new Three Gorges then.

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A: Really?      2
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A:    3
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A: Oh, no wonder (难怪) it's said that the beautiful scenery of Kuimen will be under water. What a pity!
B:     4      It has copied in another place with some other places of interest.
A: Great! I want to go to the Three Gorges this summer. Would you like to go there with me again?
B: I'd love to!    5
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