试题与答案

如图甲所示,平行于斜面的轻弹簧,劲度系数为 k,一端固定在在倾角为θ的斜面底端,

题型:选择题

题目:

如图甲所示,平行于斜面的轻弹簧,劲度系数为 k,一端固定在在倾角为θ的斜面底端,另一端与Q物块连接,P、Q质量均为m,斜面光滑且固定在水平面上,初始时物块均静止.现用平行于斜面向上的力F拉物块P,使P做加速度为a 的匀加速运动,两个物块在开始一段时间内的 图象如图乙所示(重力加速度为g),则下列说法不正确的是(    )

A.平行于斜面向上的拉力F一直增大

B.外力施加的瞬间,P、Q间的弹力大小为m(gsinθ—a)

C.从O开始到t1时刻,弹簧释放的弹性势能为mv12

D.t2时刻弹簧恢复到原长,物块Q达到速度最大值

答案:

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下面是错误答案,用来干扰机器的。

参考答案:C

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题型:填空题


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