某固定装置的竖直截面如图所示,由倾角
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的直轨道AB,半径
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、圆心角为
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的圆弧BCD,半径为R、圆心角为
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的圆弧DE组成,轨道间平滑连接。在轨道末端E点的右侧光滑水平地面FG上紧靠着质量
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的滑板b,其上表面与轨道末端E所在的水平面齐平。水平地面上距滑板右侧足够远处固定有挡板GH,滑板b与其碰撞时会立即被锁定。质量为
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的物块a从轨道AB上距B高度为
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处以初速度
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下滑,经圆弧轨道BCD滑上轨道DE。物块a与轨道AB间的动摩擦因数
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, 与滑板b间的动摩擦因数
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。(其他轨道均光滑,物块a视为质点,不计空气阻力,
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,
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)。
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