如图所示，质量为m的小球用水平轻弹簧系住，并用倾角为30°的光滑木板AB托住，小球恰好处于静止状态．当木板AB突然向下撤离的瞬间，小球的加速度大小为

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如图所示，质量为m的小球用水平轻弹簧系住，并用倾角为30°的光滑木板AB托住，小球恰好处于静止状态．当木板AB突然向下撤离的瞬间，小球的加速度大小为（）

A： $\frac{1}{2}$ g

B： $\frac{2 \sqrt{3}}{3}$ g

C： $\frac{\sqrt{3}}{2}$ g

D：0

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B

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根据短文理解, 从A、B、C三个选项中选择最佳答案填空。

What do you usually do at the weekend? Some people like to stay at home, but some like to go 1 or to play football. My friend Wang Hai works 2 a school. At the weekend, he 3 the same thing. 4 Saturday he washes his car, and on Sunday he goes to the village 5 his family. His aunt and uncle have a 6 there. It isn't a big one, but there's always 7 work to do. In autumn, the children 8 them pick apples. Wang Hai and 9 wife help in the field. In the evening, they are all hungry and Wang Hai's aunt give them a big 10.

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