一、选择题(本题共<strong><span>12</span></strong><strong><span>小题</span></strong>,<strong><span>每小题</span></strong><strong><span>4</span></strong><strong><span>分</span></strong>,<strong><span>共</span></strong><strong><span>48</span></strong><strong><span>分.在每小题给出的四个选项中</span></strong>,<strong><span>第</span></strong><strong><span>1</span></strong><strong><span>~</span></strong><strong><span>8</span></strong><strong><span>题只有一项符合题目要求</span></strong>,<strong><span>第</span></strong><strong><span>9</span></strong><strong><span>~</span></strong><strong><span>12</span></strong><strong><span>题有多项符合题目要求</span></strong>,<strong><span>全部选对的得</span></strong><strong><span>4</span></strong><strong><span>分</span></strong>,<strong><span>选对但不全的得</span></strong><strong><span>2</span></strong><strong><span>分</span></strong>,<strong><span>有选错的得</span></strong><strong><span>0</span></strong><strong><span>分)</span></strong>
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A . 点电荷在电场中所受电场力的方向一定与电场线方向相同
B . 运动的点电荷在磁场中所受洛伦兹力的方向可能与磁感线方向相同
C . 运动的点电荷在磁感应强度不为零的磁场中受到的洛伦兹力一定不为零
D . 通电长直导线在磁感应强度不为零的地方受到的安培力可能为零
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2.
如图所示,物体Q被钉牢在放于光滑水平地面的平板小车上,物体P以速率V沿水平粗糙车板向着Q运动并发生碰撞.下列说法正确的是( )
![](//tikupic.21cnjy.com/2024/05/11/2a/ae/2aaea2296ccdaf2e6294c9c5a96cb973.png)
A . 对于P与Q组成的系统动量守恒
B . 对于P、Q与小车组成的系统动量守恒
C . 对于P与小车组成的系统动量守恒
D . 对于P、Q与小车组成的系统动能守恒
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3.
如图所示是某一交变电流的i-t图像,曲线部分为正弦函数的一部分,则该交变电流的有效值为( )
![](//tikupic.21cnjy.com/2024/05/11/01/7e/017e3d1fe996dbea82326fcb6b5ceb1e.png)
A . 2A
B . 3A
C .
A
D .
A
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4.
如图所示,M和N为两个完全一样的灯泡,L是一个理想电感线圈(电阻不计),R是一个定值电阻.当电键S突然闭合或断开时,下列判断正确的是( )
![](//tikupic.21cnjy.com/2024/05/11/26/c0/26c0c4ab6980b6ea17f1b44e5ef2955c.png)
A . 电键突然闭合,N比M先亮
B . 电键闭合较长时间后,N比M亮
C . 电键突然断开,N比M先熄灭
D . 无论电键突然闭合还是断开,M和N的现象完全相同
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5.
如图所示,两倾角为θ的光滑平行导轨,质量为m的导体棒垂直放在导轨上,整个空间存在竖直向上的匀强磁场.现导体棒中通有由a到b的恒定电流,使导体棒恰好保持静止.已知磁感应强度大小为B,导体棒中电流为I,重力加速度大小为g,则平行导轨间距为( )
![](//tikupic.21cnjy.com/2024/05/11/1c/0b/1c0b81c2600431e45326698a375476fc.png)
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6.
如图所示,光滑的水平面上有大小相同、质量不等的小球A、B,小球A以速度
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Ev%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
向右运动时与静止的小球B发生正碰,碰后A球速度反向,大小为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmfrac%3E%3Cmrow%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Ev%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E4%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3C%2Fmath%3E)
, B球的速率为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmfrac%3E%3Cmrow%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Ev%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmfrac%3E%3C%2Fmath%3E)
, A、B两球的质量之比为( )
![](//tikupic.21cnjy.com/2024/05/11/12/d0/12d06fa17ece29d7e5c581c8aeb61ad3.png)
A . 5∶2
B . 2∶5
C . 3∶8
D . 8∶3
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8.
篮球运动是一项同学们喜欢的体育运动,通过篮球对地冲击力大小判断篮球的性能.某同学让一篮球从
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Eh%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E8%3C%2Fmn%3E%3Cmtext%3E%E2%80%89%3C%2Fmtext%3E%3Cmtext%3Em%3C%2Fmtext%3E%3C%2Fmath%3E)
高处自由下落,测出篮球从开始下落至反弹到最高点所用时间为t=1.5s,该篮球反弹时从离开地面至最高点所用时间为0.4s,篮球的质量m=0.5kg,重力加速度g取10
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmn%3E%2F%3C%2Fmn%3E%3Cmsup%3E%3Cmrow%3E%3Cmtext%3Es%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsup%3E%3C%2Fmath%3E)
, 不计空气阻力.则篮球对地面的平均作用力大小为( )
A . 5N
B . 10N
C . 15N
D . 20N
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9.
如图所示,下列线圈匀速转动或匀速直线运动,能产生交变电流的是( )
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10.
用同一双缝干涉实验装置做甲、乙两种光的双缝干涉实验,获得的双缝干涉条纹分别如图甲、乙所示,下列说法正确的是( )
![](//tikupic.21cnjy.com/2024/05/11/c0/9f/c09fee11405cc08f5ce5e4b8f65bab56.png)
A . 甲光的波长比乙光的波长短
B . 对同一种介质,甲光的折射率小于乙光的折射率
C . 从同种介质射向空气,甲光发生全反射的临界角大于乙光
D . 遇到同一障碍物,乙光比甲光更容易发生明显的衍射现象
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11.
(2024高二下·黑龙江期中)
如图所示,圆环形导体线圈a平放在水平桌面上,在a的正上方固定一竖直螺线管b,二者轴线重合,螺线管与电源和滑动变阻器连接成闭合电路.若将滑动变阻器的滑片P向下滑动,下列说法正确的是( )
![](//tikupic.21cnjy.com/2024/04/28/33/0a/330a37158dce333187827adbe0d32270.png)
A . 线圈a中将产生逆时针方向的感应电流(从上向下看)
B . 穿过线圈a的磁通量变小
C . 线圈a有扩张的趋势
D . 线圈a对水平桌面的压力增大
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12.
如图甲所示是远距离输电的电路示意图,乙图是用电器两端的电压随时间变化的图像.已知降压变压器的原线圈与副线圈的匝数之比
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3En%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E3%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmn%3E%3A%3C%2Fmn%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3En%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E4%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E4%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E%3A%3C%2Fmn%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmath%3E)
, 输电线的总电阻R=20Ω,降压变压器的输出功率
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3EP%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E4%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E8%3C%2Fmn%3E%3Cmn%3E8%3C%2Fmn%3E%3Cmtext%3E%E2%80%89%3C%2Fmtext%3E%3Cmtext%3Ek%3C%2Fmtext%3E%3Cmtext%3EW%3C%2Fmtext%3E%3C%2Fmath%3E)
, 发电机的输出电压为250V,电路中的升压变压器和降压变压器均为理想变压器.则下列结论正确的是( )
![](//tikupic.21cnjy.com/2024/05/11/71/c8/71c89ed60e278984c4cfa9f3f10d5763.png)
A . 降压变压器原线圈中电流的频率为100Hz
B . 流过输电线的电流大小为10A
C . 发电机的输出功率为92kW
D . 升压变压器原、副线圈的匝数之比
二、实验题(本题共<strong><span>2</span></strong><strong><span>小题</span></strong><strong><span>,</span></strong><strong><span>共</span></strong><strong><span>18</span></strong><strong><span>分)</span></strong>
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13.
某小组同学在做“用单摆测量重力加速度”的实验中,操作步骤如下:
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(1)
用10分度的游标卡尺测量摆球的直径如图甲所示,可读出摆球的直径为d=
mm.
![](//tikupic.21cnjy.com/2024/05/11/7d/01/7d0139e8974d3295df4c8745395f640d.png)
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(2)
测单摆的振动周期时,以摆球在最低位置处为计时基准位置,摆球以后每从同一方向经过摆球的最低位置记数一次,用秒表记录摆球从同一方向n次经过摆球的最低位置时的时间t,则T=;若摆线长为l,则重力加速度g=.(均用题中所给物理量符号表示)
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(3)
测量出多组周期T、摆长L数值后,画出
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsup%3E%3Cmrow%3E%3Cmi%3ET%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsup%3E%3C%2Fmath%3E)
-L图像如图乙所示,此图线斜率的物理意义是____.
![](//tikupic.21cnjy.com/2024/05/11/f8/45/f8454a686f1c34550c95d344da67bb02.png)
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14.
如图甲所示是“验证动量守恒定律”的装置,气垫导轨上安装了1、2两个光电门,两滑块上均固定一相同的竖直遮光条.
![](//tikupic.21cnjy.com/2024/05/11/66/8b/668b63d93d877eeed23b5da406bd1bb8.png)
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(1)
用螺旋测微器测量滑块上的遮光条宽度,测量结果如图乙所示,读数为d=
mm.
![](//tikupic.21cnjy.com/2024/05/11/29/d1/29d1eb8c866893448e089917c73a4b03.png)
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(2)
实验前,接通气源后,在导轨上轻放一个滑块,给滑块一初速度,使它从轨道右端向左运动,发现滑块通过光电门1的时间小于通过光电门2的时间.为使导轨水平,可调节Q使轨道右端(填“升高”或“降低”)一些.
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(3)
测出滑块A和遮光条的总质量为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3EA%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
, 滑块B和遮光条的总质量为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3EB%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
, 将滑块B静置于两光电门之间,将滑块A静置于光电门1右侧,推动滑块A,使其获得水平向左的初速度,经过光电门1后与滑块B发生碰撞且被弹回,再次经过光电门1.光电门1先后记录的挡光时间分别为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%CE%94%3C%2Fmtext%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Et%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
和
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%CE%94%3C%2Fmtext%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Et%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
, 光电门2记录的挡光时间为△
3 , 实验中两滑块的质量应满足
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3EA%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Em%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmtext%3EB%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
(填“>”“<”或“=”).
-
(4)
滑块A、B碰撞过程中,若表达式成立,则可验证动量守恒定律成立;若表达式成立,则此碰撞为弹性碰撞.(均用题中所给物理量字母符号表示)
三、计算题(本题共<strong><span>3</span></strong><strong><span>小题</span></strong><strong><span>,</span></strong><strong><span>共</span></strong><strong><span>34</span></strong><strong><span>分.作答时应写出必要的文字说明、方程式和重要的演算步骤.只写出最后答案的不能得分.有数值计算的题</span></strong><strong><span>,</span></strong><strong><span>答案中必须明确写出数值和单位)</span></strong>
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15.
如图所示,实线和虚线分别表示沿x轴传播的一列简谐横波在
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Et%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmath%3E)
和
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Et%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmtext%3E%E2%80%89%3C%2Fmtext%3E%3Cmtext%3Es%3C%2Fmtext%3E%3C%2Fmath%3E)
时刻的波形图,已知在
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Et%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmath%3E)
时刻,介质中x=0.6m处的质点P沿y轴正方向运动.求:
![](//tikupic.21cnjy.com/2024/05/11/b3/b9/b3b9cb69637aa2840742ffe1d0f9e377.png)
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(2)
若T>0.2s,则从
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Et%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmath%3E)
时刻开始,介质中x=0.1m处的质点Q第4次到达波谷所用的时间.
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16.
如图所示,在y>0的区域内存在匀强磁场,磁感应强度大小为B、方向垂直于xOy平面并指向纸外.一质量为m、电荷量为-q(q>0)的带电粒子以速度
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3Ev%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E0%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3C%2Fmath%3E)
从O点射入磁场,入射方向在xOy平面内,且与x轴正方向的夹角为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%CE%B8%3C%2Fmtext%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmo%3E%C2%B0%3C%2Fmo%3E%3C%2Fmath%3E)
.粒子重力不计,求:
![](//tikupic.21cnjy.com/2024/05/11/81/a0/81a0a9d16aae92af229e8503526fd26b.png)
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17.
如图所示,足够长的U形导体框架的宽度L=0.5m,下端有一阻值为
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3ER%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E8%3C%2Fmn%3E%3Cmtext%3E%CE%A9%3C%2Fmtext%3E%3C%2Fmath%3E)
的电阻,导轨其余部分电阻忽略不计,其所在平面与水平面成
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%CE%B8%3C%2Fmtext%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E7%3C%2Fmn%3E%3Cmo%3E%C2%B0%3C%2Fmo%3E%3C%2Fmath%3E)
角.有一磁感应强度大小为B=0.8T的匀强磁场,方向垂直于导体框平面斜向上.一质量m=0.4kg、电阻
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmsub%3E%3Cmrow%3E%3Cmi%3ER%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsub%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmtext%3E%CE%A9%3C%2Fmtext%3E%3C%2Fmath%3E)
的导体棒MN垂直跨放在U形框架上,某时刻起将导体棒由静止释放.已知导体棒与框架间的动摩擦因数
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3C%2Fmath%3E)
,
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3Es%3C%2Fmn%3E%3Cmn%3Ei%3C%2Fmn%3E%3Cmn%3En%3C%2Fmn%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E7%3C%2Fmn%3E%3Cmo%3E%C2%B0%3C%2Fmo%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E6%3C%2Fmn%3E%3C%2Fmath%3E)
,
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3Ec%3C%2Fmn%3E%3Cmn%3Eo%3C%2Fmn%3E%3Cmn%3Es%3C%2Fmn%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E7%3C%2Fmn%3E%3Cmo%3E%C2%B0%3C%2Fmo%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E8%3C%2Fmn%3E%3C%2Fmath%3E)
, 重力加速度g取10
![](//math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmn%3E%2F%3C%2Fmn%3E%3Cmsup%3E%3Cmrow%3E%3Cmtext%3Es%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsup%3E%3C%2Fmath%3E)
, 求:
![](//tikupic.21cnjy.com/2024/05/11/e6/c8/e6c82752f97976b6fe7536a7e0c2fc45.png)
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(2)
导体棒速度大小v=1.5m/s时的加速度大小;
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(3)
从导体棒开始下滑到速度刚达到最大时的过程中,导体棒沿斜面向下运动的位移为x=10m,整个回路中产生的焦耳热.