webclass

{ "exam_name": "大学物理期末试卷", "exam_des": "总分100分, 考试时间100分钟.", "exam_type": { "short_answer": { "name": "简答题", "des": "每题5分" }, "fill_in_the_blank": { "name": "填空题", "des": "每空2分" }, "true_false": { "name": "判断题", "des": "每题2分" }, "multiple_choice": { "name": "单选题", "des": "每题4分" }, "calculation": { "name": "计算题", "des": "每题10分" } }, "calculation": { "301": { "subject": "一列机械波沿轴正向传播，$t=0$时的波形如如图所示．已知波速为$10m/s$, 波长为$2m$, 求1)波动方程, 2)P点的振动方程", "figure": { "path": "4-8.png", "width": 0.6 }, "answer": "", "comment": "", "chapter": "4" } }, "short_answer": { "101": { "subject": "在以下几种运动中，质点的切向加速度、法向加速度以及加速度哪些为零哪些不为零？(1) 匀速直线运动；(2) 匀速曲线运动；(3) 变速直线运动；(4) 变速曲线运动.", "answer": "(1) 质点作匀速直线运动时，其切向加速度、法向加速度及加速度均为零；(2) 质点作匀速曲线运动时，其切向加速度为零，法向加速度和加速度均不为零；(3) 质点作变速直线运动时，其法向加速度为零，切向加速度和加速度均不为零；(4) 质点作变速曲线运动时，其切向加速度、法向加速度及加速度均不为零", "comment": "", "chapter": 1 } }, "fill_in_the_blank": { "101": { "subject": "在物理学中描述物质运动的物理量一般可分为标量和矢量，其中矢量主要有位移, $\\underline{~~~~~~~~~~~~}$, $\\underline{~~~~~~~~~~~~}$等.", "answer": [ "速度", "加速度" ], "comment": "", "chapter": 1 }, "201": { "subject": "质量为10g的子弹沿x轴正向以$100m/s$的速率射入一木块后与木块一起沿X轴正向以$10m/s$的速率前进，在此过程中木块所受冲量的大小为$\\underline{~~~~~~~~~~~~}$ N·s.", "answer": [ "0.9" ], "comment": "", "chapter": 2 }, "202": { "subject": "某质点在力$\\vec{F} = (5+4x)\\vec{i}$(N)的作用下沿x轴作直线运动。在从x=0m移动到x=10m的过程中,力F所做功为 $\\underline{~~~~~~~~~~~~}$.", "answer": [ "250J" ], "comment": "$\\int_{0}^{10}(5+4x)dx$", "chapter": 2 }, "203": { "subject": "质量为10kg的物体在水平面上作直线运动，初速度为5 m/s，在摩擦力作用下，当物体停止时，摩擦力所做的功为 $\\underline{~~~~~~~~~~~~}$.", "answer": [ "125J" ], "comment": "$\\frac{1}{2}mv^{2}$", "chapter": 2 } }, "true_false": { "101": { "subject": "平均速率等于平均速度的大小( $~~~~$ )", "answer": "false", "comment": "速率是路程对时间的导数，速度是位矢对时间的导数", "chapter": 1 }, "102": { "subject": "质点是力学中最简单的一个物理模型( $~~~~$ )", "answer": "true", "comment": " ", "chapter": 1 }, "103": { "subject": "矢量的标量积大小等于两个矢量的模与其夹角(小于$180^{o}$)余弦值乘积.( $~~~~$ )", "answer": "true", "comment": " ", "chapter": 1 }, "104": { "subject": "直角坐标系的方向矢量关系满足矢量叉乘的关系( $~~~~$ )", "answer": "true", "comment": " ", "chapter": 1 }, "201": { "subject": "牛顿第二定律适用于任意参考系( $~~~~$ )", "answer": "false", "comment": "", "chapter": 2 }, "202": { "subject": "冲量的方向与质点动量方向一致( $~~~~$ )", "answer": "false", "comment": "", "chapter": 2 }, "203": { "subject": "内力不改变系统的总动量( $~~~~$ )", "answer": "true", "comment": "", "chapter": 2 }, "204": { "subject": "系统的总动量守恒并不意味着系统内每一个质点的动量都保持不变( $~~~~$ )", "answer": "true", "comment": "", "chapter": 2 }, "205": { "subject": "若系统所受合外力不为零，但是合外力在某一方向的分量始终为零，则系统在该方向上的总动量守恒( $~~~~$ )", "answer": "true", "comment": "", "chapter": 2 } }, "multiple_choice": { "101": { "subject": " 质点沿半径为R的圆周作匀速率运动，每t秒转一圈，在2t时间间隔中，其平均速度大小和平均速率大小分别为( $~~~~$ )", "choices": { "A": " $ \\displaystyle \\frac{2\\pi R }{t}$, $\\displaystyle \\frac{2\\pi R }{t}$ ", "B": "0, $\\displaystyle \\frac{2\\pi R }{t}$", "C": "0, 0", "D": "$\\displaystyle \\frac{2\\pi R }{t}$,0" }, "figure": "", "answer": "B", "comment": "", "chapter": 1 }, "102": { "subject": "一运动质点在某瞬时位于矢径的端点处，其速度大小为( $~~~~$ )", "choices": { "A": " $ \\displaystyle \\frac{dr }{dt} $ ", "B": "$ \\displaystyle \\frac{d \\vec{r} }{dt} $", "C": "$ \\displaystyle \\frac{d |\\vec{r}| }{dt} $", "D": "$\\sqrt{ ( \\displaystyle \\frac{dx}{dt})^{2} + ( \\displaystyle \\frac{dy}{dt})^{2}}$ " }, "figure": { "path": "beam-kine.PNG", "width": 0.4 }, "answer": "D", "comment": "", "chapter": 1 }, "201": { "subject": "牛顿第一定律告诉我们( $~~~~$ )", "choices": { "A": "物体不受力也能保持本身的运动状态", "B": "物体的运动状态不变, 则一定不受力", "C": "物体的运动方向必定和受力方向一致", "D": "物体受力后才能运动" }, "figure": "", "answer": "A", "comment": "", "chapter": 2 }, "202": { "subject": "用细绳系一小球使之在竖直平面内作圆周运动, 小球在任意位置( $~~~~$ )", "choices": { "A": "绳子的拉力和重力是惯性离心力的反作用力", "B": "绳子的拉力和重力的合力是惯性离心力的反作用力,物体的运动状态不变, 则一定不受力", "C": "都有切向加速度", "D": "都有法向加速度" }, "figure": "", "answer": "D", "comment": "", "chapter": 2 }, "203": { "subject": " 一个物体受到几个力的作用, 则( $~~~~$ )", "choices": { "A": "运动速率一定改变", "B": "必定对另一些物体产生力的作用", "C": "运动状态一定改变", "D": "必定产生加速度" }, "figure": "", "answer": "B", "comment": "", "chapter": 2 }, "204": { "subject": " 一质量为60kg的人静止在一个质量为600kg且以2m/s的速率向河岸行驶的木船上，河水是静止的，其阻力不计。现在人以水平速度v沿着船前进的方向向河岸跳去，该人跳起后，船速减为原来的一半，求v的大小( $~~~~$ )", "choices": { "A": "20m/s", "B": "10m/s", "C": "12m/s", "D": "11m/s" }, "figure": "", "answer": "D", "comment": "", "chapter": 2 }, "205": { "subject": "下面哪种说法是正确的( $~~~~$ )", "choices": { "A": "系统不受外力作用，则它的机械能和动量都守恒", "B": "系统所受的外力矢量和为零，内力都是保守力，则机械能和动量都守恒", "C": "系统所受的外力矢量和不为零，内力都是保守力，则机械能和动量都不守恒", "D": "系统不受外力的作用，内力都是保守力，则机械能和动量都守恒" }, "figure": "", "answer": "D", "comment": "A:非保守力做功. B: 系统的合外力矢量和为零，合外力做功不一定为零,合外力矩不一定为零; C: 外力做功为零时，机械能守恒", "chapter": 2 }, "206": { "subject": "下面哪种说法是正确的( $~~~~$ )", "choices": { "A": "物体的运动方向和合外力的方向不一定相同", "B": "物体受到几个力的作用后一定产生加速度", "C": "物体运动的速率不变, 所受合外力一定为零", "D": " 物体的运动速度很大,所受合外力也很大" }, "figure": "", "answer": "A", "comment": " ", "chapter": 2 }, "207": { "subject": "质点系的内力会改变( $~~~~$ )", "choices": { "A": "系统的总质量", "B": "系统的总动量", "C": "系统的总动能", "D": "系统的总角动量" }, "figure": "", "answer": "C", "comment": " ", "chapter": 2 }, "208": { "subject": "一质点作匀速率圆周运动时( $~~~~$ )", "choices": { "A": "它的动量不变,动能不变", "B": "它的动量不变,动能不断改变", "C": "它的动量不断改变,动能不变", "D": "它的动量不断改变,动能不断改变" }, "figure": "", "answer": "C", "comment": " ", "chapter": 2 }, "209": { "subject": "A，B两木块质量分别为$m_{A}$和$m_{B}$，且$m_{B}= 2m_{A}$, 两者用一轻弹簧连接后静止于光滑水平桌面上.若用外力将两木块推近使弹簧被压缩，然后将外力撤去，则此后两木块运动动能之比$E_{A} : E_{B}$ 为 $\\underline{~~~~~~~~~~~~}$", "choices": { "A": "1:2", "B": "2:1", "C": "$1:\\sqrt{2}$", "D": "$\\sqrt{2}:1$" }, "figure": "", "answer": "B", "comment": "$m_{A}v_{A}= m_{B}v_{B}$, \\\\ $v_{A}:v_{B} = 2:1$ \\\\ $E_{A}:E_{B} = \\frac{1}{2}m_{A}v_{A}^{2}: \\frac{1}{2}m_{B}v_{B}^{2}= 2:1$", "chapter": 2 }, "210": { "subject": "下面说法正确的是( $~~~~$ )", "choices": { "A": "外力不改变系统的动量", "B": "内力不改变质点系内质点的动量", "C": "内力不改变质点系的机械能", "D": "孤立系统的内力不改变系统的总能量" }, "figure": "", "answer": "D", "comment": " ", "chapter": 2 }, "211": { "subject": " 对功的概念,下面说法正确的是( $~~~~$ )", "choices": { "A": "保守力作正功时，系统内相应的势能增加", "B": "质点运动经一闭合路径，保守力对质点作的功为零", "C": "作用力与反作用力大小相等、方向相反，所以两者所作功的代数和必为零" }, "figure": "", "answer": "B", "comment": " c)功是力与它的方向上所做的位移的乘积", "chapter": 2 }, "212": { "subject": "下面说法正确的是( $~~~~$ )", "choices": { "A": "质点所受合外力为零，则外力对其做功为零", "B": "质点系所受合外力矢量和为零，则外力对系统做功为零", "C": "质点系不受外力，则系统的动能不变", "D": "质点系内有非保守内力，则系统的机械能不守恒" }, "figure": "", "answer": "A", "comment": " ", "chapter": 2 }, "301": { "subject": "一物体作简谐振动，振动方程为$x = Acos(\\omega t + \\pi /4)$．在$t = T/4$(T为周期)时刻，物体的加速度为( $~~~~$ )", "choices": { "A": "$-\\frac{1}{2}\\sqrt{2}A \\omega^{2}$", "B": "$ \\frac{1}{2}\\sqrt{2}A \\omega^{2}$", "C": "$-\\frac{1}{2}\\sqrt{3}A \\omega^{2}$", "D": "$ \\frac{1}{2}\\sqrt{3}A \\omega^{2}$" }, "figure": "", "answer": "B", "comment": "", "chapter": "4" }, "302": { "subject": "一质点作简谐振动．其运动速度与时间的曲线如图所示．若质点的振动规律用余弦函数描述．则其初相位应为( $~~~~$ )", "choices": { "A": "$ \\pi / 6$", "B": "$ 5\\pi / 6$", "C": "$-5\\pi / 6$", "D": "$-\\pi / 6$" }, "figure": { "path": "4-1.png", "width": 0.4 }, "answer": "C", "comment": "", "chapter": "4" }, "308": { "subject": "弹性系数为$k$的轻质弹簧与质量为$m$的重物组成的弹簧系统在光滑水平面上作简谐振动, 重物运动方程为$x=Acos(\\omega t + \\varphi)$, 弹性力在半个周期内所作的功为( $~~~~$ )", "choices": { "A": "$ kA^{2} $", "B": "$ kA^{2}/2$", "C": "$ kA^{2}/4$", "D": "$ 0 $" }, "figure": { "path": "", "width": 0.4 }, "answer": "D", "comment": "", "chapter": "4" } } }