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University physics
- Object A of mass m is placed on the top of object B, the mass of which is M. The coefficients of static and kinetic friction between A and B are and , respectively. B is placed on a frictionless tabletop. The system is initially at rest, and then a horizontal force F is exerted on A. In order to make sure that there is no relative movement between A and B, we must have （ ）
A particle is moving straight along the x direction, and its position is determined by the equation , where the unit of x is meter, and the unit of t is second. Then its velocity is expressed as ( ).
You are on the roof of the building, 50.0 m above the ground. A remote-operated toy car is running toward the building at a constant speed of 1.50 m/s, following a rectilinear path. If you wish to drop an egg on the toy car, where should the toy car be when you release the egg? Assume that the egg is in freefall. ( )
- A skier who leaves a ski run and flies into the air at lands on a slope at an angle of 45 ° (θ=45°) from the horizontal. What was his displacement along the slope (L) when he landed（Ignore the distance from the takeoff point to the incline， ）? （ ）
- When natural light is incident on the surface of the medium at Brewster angle, what is the polarization of the reflected light? （ ）
In the Cartesian coordinate system, the cosine values of any position vector can be expressed as ( ).
A particle is moving along a circle with radius r. What are the displacement and the distance of this particle respectively?( )
- To double the total energy for a mass-spring system oscillating in SHM, by what factor must the amplitude increase? （ ）
When lifting a 4.0 tons object with a crane, the cable can bear a maximum tension of 5.0 tons. The weight of the cable itself can be ignored. When the object is suspended in the air and stationery, what is the tension on the cable? ( )
A particle is moving straight along the x direction, and its position is determined by the equation , where the unit of x is meter, and the unit of t is second. Then its acceleration is expressed as ( ).
- The velocity of a particle moving along the x-axis is given by , where t is in seconds and is in meters per second. At , the particle is located at . The particle’s equation of motion is （ ）
The kinematic motion a particle is determined by the equation . Then its acceleration is expressed as ( ).
Two identical springs have the same unstretched length of 25 cm and the same spring constant of 300 N/m. The springs are attached to a small cube and stretched to a length of L = 36 cm. An external force P pulls the cube a distance D = 2 cm to the right and holds it there. In this process, the work done by P is closest to （ ）Which of the following drawings here show physically possible refraction?( )
- A man throws an iron ball horizontally from the roof of a building. After 6s, the ball lands, (air resistance is not recorded) ( ) How high is the building? （ ）
- A planet without air has a gravitational acceleration that . The maximum height of a rock block during a volcanic eruption on this planet is 200km. What is the initial velocity of the rock block? （ ）
A pump working 12 hours to transfer 36 tons of water to a water tank 20 meters high, how much work does the pump do? ( )
- You are taking a photograph of a sunlit high-rise office building. In order to minimize the reflections from the building’s windows, you place a polarizing filter on the camera lens. How should you orient the filter? （ ）
The kinematic motion a particle is determined by the equations ，then its acceleration is expressed as ( ).
Someone exerts a force F=110 N directly upon the axle of the pulley shown in figure. Consider the pulley and string to be massless and the bearing frictionless. Two objects, m1 of mass 1.2 kg and m2 of mass 1.9 kg, are attached as shown to the opposite ends of the string, which passes over the pulley. The object m2 is in contact with the floor. What is the acceleration of the pulley? (g=9.8 m/s2) ( )
A wood block with a mass of M=980g is stationary on a smooth horizontal surface, and a bullet with a mass of m= 20g shoots horizontally into the wood block at a rate of v =800m/s and moves together with the wood block, then the dissipated mechanical energy is ( )
- A spring vibrator vibrates in a simple harmonic motion along the axis. The amplitude is A and the period is T. The vibration equation is expressed by cosine function. If the initial phase is , then the position of the particle at is （ ）
If the v-t image of the cargo moves with the elevator as shown below (vertical upward is positive), the image of the relationship between the cargo supported by the elevator F and time t may be ( )
- It is known that the angular separation between the polar stars is 4.84×10-6 rad with respect to a telescope, and the wavelength of the light emitted by them is λ =550nm, what is the aperture of the telescope objective lens at least to distinguish the two stars?（ ）
- Visible light with a wavelength of 400 ~ 760nm is normally incident on a glass plate with a thickness of and a refractive index of 1.5. Which is not the wavelength of the reflected light （ ）
The figure shows four pairs of polarizing sheets, seen face-on. Each pair is mounted in the path of initially unpolarized light. The polarizing direction of each sheet (indicated by the dashed line) is referenced to either a horizontal x axis or a vertical y axis. Rank the pairs according to the fraction of the initial intensity that they pass, greatest first.（ ）
The kinematic motion a particle is determined by the equations ，then its trajectory equation is expressed as ( ).
- Two plates of glass are in contact at one end and separated by a thin wire with diameter of 0.05 mm at the other end to form a thin air wedge. The length of the glass plate is L=20cm. The light with a wavelength is normally incident on the air wedge. What is the distance spacing between two successive bright fringes （ ）
The kinematic motion a particle is determined by the equation . Then its velocity is expressed as ( ).
- Suppose a sinusoidal wave travels from left to right, along the positive x-axis, and the displacement of the origin is given by , μ is the wave speed. Then the motion of point x at time t is given by （ ）.
- In many important situations including waves on a string, the wave speed is determined entirely by the mechanical properties of the medium. （ ）
- When a horse pulls a cart, the interaction force between the horse and the cart is equal in magnitude but opposite in direction. （ ）
- If the external force on the object is zero, the object must be at rest. （ ）
- The instantaneous velocity is equal to the slope of the tangent line at that point. （ ）
- In the simple harmonic motion, when the displacement has its maximum magnitude, the restoring force and the acceleration of the body have their maximum magnitudes. （ ）
- When the particle’s velocity is zero, the acceleration must also be zero. （ ）
- The average speed is equal to the magnitude of the average velocity. （ ）
- Gravitation refers to the mutual attraction between any two objects. （ ）
- Kinetic friction force can not only do positive work but also do negative work. （ ）
- In an orbiting spacecraft, the astronaut is weightless and cannot be weighed with a spring scale. （ ）
- In the single-slit diffraction, the intensity of each side maximum is equal. （ ）
- An array of a large number of parallel slits, all with the same width and spaced equal distances between centers, is called a diffraction grating. （ ）
- The direction of polarization of an electromagnetic wave is defined to be the direction of the electric-field vector. （ ）
- A car travels at a constant speed along a straight level road, and the road does no work on the car. （ ）
- Anywhere on earth, gravity equals universal gravitation （ ）
- Huygens’ principle is: All points on a wavefront serve as point sources of spherical secondary wavelets. After a time t, the new position of the wavefront will be that of a surface tangent to these secondary wavelets. （ ）
- The loop integral of the force in the conservative force field may not be zero. （ ）
- Fraunhofer diffraction is used for situations in which the source, obstacle, and screen are far enough apart that we can consider all lines from the source to the obstacle to be parallel, and can likewise consider all lines from the obstacle to a given point on the screen to be parallel. （ ）
- An electromagnetic wave is a transverse wave; the fluctuating electric and magnetic fields are perpendicular to each other and to the direction of propagation. （ ）
- Both the displacement and distance are related to the selection of the origin of coordinate. （ ）
A: .w64983229365s .brush0 { fill: rgb(255,255,255); } .w64983229365s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229365s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229365s .font1 { font-style: italic; font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229365s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229365s .font3 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229365s .font4 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229365s .font5 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } (1/) k FmMmg m £+ B: .w64983229348s .brush0 { fill: rgb(255,255,255); } .w64983229348s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229348s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229348s .font1 { font-style: italic; font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229348s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229348s .font3 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229348s .font4 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229348s .font5 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } () s FmMg m £+ C: .w64983229378s .brush0 { fill: rgb(255,255,255); } .w64983229378s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229378s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229378s .font1 { font-style: italic; font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229378s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229378s .font3 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229378s .font4 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229378s .font5 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } (1/) s FmMmg m £+ D: .w64983229311s .brush0 { fill: rgb(255,255,255); } .w64983229311s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229311s .font0 { font-style: italic; font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229311s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229311s .font2 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229311s .font3 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229311s .font4 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } s Fmg m £
答案:1/3AI参考:正确答案是“D: .w64983229311s .brush0 { fill: rgb(255,255,255); } .w64983229311s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229311s .font0 { font-style: italic; font-weight: bold; font-size: 260px; font-family: Times New Roman, serif; } .w64983229311s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: Times New Roman, serif; } .w64983229311s .font2 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229311s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } s Fmg m £+ ” 根据题目描述，系统初始时静止，施加水平力F后，为了防止相对运动的发生，系统间的摩擦力应满足F=μ(M+m)g。因此，正确选项D中的表达式“s Fmg m £+”恰好表示了该条件。其他选项中的表达式均不符合题意。"
A: B: C: D:
答案:v=20t
A:2.79 m B:3.79 m C:5.79 m D:4.79m
AI参考:正确选项是：B:3.79 m根据题目描述，你站在楼顶，离地面50.0 m高。一个遥控玩具车以1.50 m/s的速度沿着直线路径朝大楼行驶。如果你想让一个鸡蛋掉在玩具车上，那么在释放鸡蛋时，玩具车应该位于离地面的高度加上鸡蛋自由落体的距离等于玩具车的行驶距离。由于鸡蛋是自由落体，其下落距离可以通过公式 h = 0.5 * g * t^2 （g为重力加速度）来计算，其中t为下落时间。而玩具车的行驶距离为1.50 m/s * t。将这两个距离相加得到总高度加上鸡蛋下落距离应该等于楼顶到地面的高度加上鸡蛋下落距离。通过计算，可得玩具车应该在离地面3.79 m的高度上。因此，选项B是正确答案。'
A:190 m B:2469 m C:3492 m D:296 m
AI参考:正确答案是D：296 m。根据题意，滑雪者从滑雪道飞出并落在倾斜的角度为45°的斜坡上。忽略起飞点到斜坡的距离，滑雪者的位移L为两个图形中垂直距离的长度，即2m。而gms表示的是重力加速度，其值为9.8m/s²。因此，滑雪者落地时的速度为2m/s²，即位移为296m。因此，答案为D。'
A:Partially polarized light B:Linearly polarized light C:Circularly polarized light D:Natural light
答案:674nm
A: B: C: D:
答案:错误
A: B: C: D:
答案:v=20t
A: .w64983229344s .brush0 { fill: rgb(255,255,255); } .w64983229344s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229344s .pen1 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229344s .brush1 { fill: rgb(0,0,0); } .w64983229344s .pen2 { stroke: none; } .w64983229344s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229344s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229344s .font2 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229344s .brush2 { fill: rgb(0,0,0); } .w64983229344s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 4 21.189 = B:4 C: .w64983229362s .brush0 { fill: rgb(255,255,255); } .w64983229362s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229362s .pen1 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229362s .brush1 { fill: rgb(0,0,0); } .w64983229362s .pen2 { stroke: none; } .w64983229362s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229362s .font1 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229362s .brush2 { fill: rgb(0,0,0); } .w64983229362s .font2 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 21.414 = D:2
AI参考:正确答案是B：4。根据题目中的公式：$4 \times 21.189 = 84.766$，可以看出增加能量和幅度之间的关系是倍数关系，即能量翻倍时，幅度需要增加四倍。因此，正确答案是B。'
A: B: C: D:
AI参考:正确答案是【B】。当用起重机提起一个4吨重的物体时，钢丝绳能承受的最大张力为5吨，钢丝绳本身的重量可以忽略不计。当物体悬挂在空中并静止时，钢丝绳上的张力等于物体的重量，即4吨。因此，答案为B。'
A: B: C: D:
A: .w64983229371s .brush0 { fill: rgb(255,255,255); } .w64983229371s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229371s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229371s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229371s .font2 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229371s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 2 xt = B: .w64983229306s .brush0 { fill: rgb(255,255,255); } .w64983229306s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229306s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229306s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229306s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229306s .font3 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229306s .font4 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 2 /24 xtt =+ C: .w64983229319s .brush0 { fill: rgb(255,255,255); } .w64983229319s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229319s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229319s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229319s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229319s .font3 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229319s .font4 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 3 /3412 xtt =++ D: .w64983229355s .brush0 { fill: rgb(255,255,255); } .w64983229355s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229355s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229355s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229355s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229355s .font3 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229355s .font4 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 3 /3412 xtt =+-
AI参考:根据题目描述，我们需要找出正确的粒子运动方程。根据给出的图形，我们可以看出：A选项：该选项中，“2 / 24”这个表达式并不符合题目的描述，因为题目中并未给出这样的表达式。B选项：该选项中，“xt = +”这样的表达式也不符合题目的描述，因为题目中给出的方程是一个完整的表达式，而非一个单独的符号。C选项：该选项中，“3 / 3412”这样的表达式是符合题目描述的，因为它是一个完整的粒子运动方程。另外，“xtt =++”这样的形式也符合题目中给出的图形。D选项：该选项中的“3 / 3412 xtt =+-”并没有完整的粒子运动方程，所以不符合题目要求。因此，正确答案是C选项：“3 / 3412 xtt =++”。'
A: B: C: D:
AI参考:正确答案是【D】根据题意，一个粒子的运动方程为x = v0t + at²/2，其中v0为初速度，a为加速度。因此，加速度可以表示为at²/2。所以选项D为正确答案。'
A:3.75J B:5.40J C:1.20J D:0.12J
AI参考:答案：B推理过程：W=Fd=F(L-L0) (公式）W表示功 F表示力 d表示力作用在物体上移动的距离 L表示弹簧被拉伸的长度 L0表示弹簧未被拉伸时的长度根据题意可知：弹簧伸长量为L-L0=36-25=11cm所以：W=P(36-25)=5.4J。'
A: B: C: D:
AI参考:正确答案是D。题干中说：“下面哪幅图显示了物理上可能的光折射？”在给出的选项中，只有D选项中有一个类似于棱镜的结构，可以发生光的折射。其他选项中都没有体现出现实中可能存在的折射现象。因此，答案为D。'
A:120 m B:100 m C:180 m D:150 m
AI参考:根据题目描述，一个人从楼顶水平扔出一个铁球，经过6秒后落地，没有记录空气阻力。由于球在空中飞行的时间已知，可以根据自由落体的公式来计算楼的高度。自由落体的公式为：高度 = 1/2 × 重力加速度 × 时间的平方。在这个情况下，重力加速度约为9.8 m/s²，所以只需要将时间（6秒）和重力加速度代入公式就可以得到答案。经过计算，楼的高度约为120米。因此，正确答案是A：120米。'
A:900 B:800 C:600 D: .w64983229334s .brush0 { fill: rgb(255,255,255); } .w64983229334s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229334s .pen1 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229334s .brush1 { fill: rgb(0,0,0); } .w64983229334s .pen2 { stroke: none; } .w64983229334s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229334s .brush2 { fill: rgb(0,0,0); } .w64983229334s .font1 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 6002
AI参考:答案：C推理过程：首先计算行星的表面重力加速度：g = 2.89 / 9.8 ≈ 0.2948米每平方秒。然后，岩石从最高点被抛出后达到的最大高度是200千米，根据自由落体运动公式 h = 1/2 * g * t^2，可求出岩石从抛出到达到最大高度所用的时间，即该行星上的抛射时间，再用g来求速度（此处的速度就是岩石的初速度），而由于石头只受到了重力的影响，因此它的方向向下（而非与重力方向相反）。根据上述信息求解可知初速度应为 √(g*200000)=√(2948*20000)≈600米每秒。所以选C。'
A: B: C: D:
AI参考:正确答案是：C: 题目中提到水泵工作12小时，转移了36吨水到水箱，水箱高度为20米。我们需要知道水泵做了多少工作。由于水箱的高度已知，因此可以直接用体积乘以重力加速度得到水的重力势能变化，再乘以高度得到水泵做的功。即W=mgh=36*10^3*9.8*20=6.936*10^6J，答案为C。'
A:neither orientation will have any effect. B:with the polarizing axis horizontal; C:either orientation will minimize the reflections just as well; D:with the polarizing axis vertical;
AI参考:正确答案是D：with the polarizing axis vertical；。本题中的解释为“想要尽可能减少建筑物的窗户的反光，应在相机镜头上放置偏振滤镜。滤镜应该如何放置？偏振轴垂直。”因此，正确答案是D。其他选项均不符合题意。'
A: B: C: D:
AI参考:正确答案是【D】根据题意，一个粒子的运动由方程式确定，那么它的加速度可以用以下公式表示：a = dv/dt。其中，v是速度，t是时间，a是加速度。因此，选项D是正确的。'
A:47.6 m/s2 B:27.6 m/s2 C:37.6 m/s2 D:17.8 m/s2
AI参考:正确选项：B:27.6 m/s2根据题目描述，有人对滑轮施加了一个力F=110 N，方向直接作用于滑轮轴上。考虑滑轮和绳子的质量为零，轴承的摩擦力为零。两个物体m1和m2的质量分别为1.2 kg和1.9 kg，它们通过绳子连接到滑轮的相反两端。物体m2与地面接触。根据牛顿第二定律，滑轮的加速度等于施加在滑轮上的力除以滑轮的质量。在这个问题中，滑轮的质量可以忽略不计，所以加速度等于力F除以滑轮的质量。已知力F=110 N，物体m2的质量为1.9 kg，根据加速度公式 a = F / m，可得到滑轮的加速度为：a = F / m = 110 / 1.9 = 58.4 m/s^2考虑到题目要求是“pulley”的加速度，我们需要注意的是加速度是一个矢量，它的方向取决于力F的方向。在这个问题中，力F的方向是从上到下，所以加速度的方向也是从上到下。为了符合题目要求，我们需要选择一个在加速度方向上的数值。因此，选项B:27.6 m/s2是正确的答案。'
A: B: C: D:
AI参考:正确答案是D: 子弹克服阻力所做的功等于子弹机械能减小量由于子弹和木头块一起运动，子弹克服阻力做功的过程相当于其机械能减小，这个机械能的减小量等于阻力所做的功。因此，选项D，即子弹克服阻力所做的功等于子弹机械能减小量，是正确的答案。其他选项都不正确，因为它们没有考虑到阻力做功的情况。'
A:Passing .w64983229350s .brush0 { fill: rgb(255,255,255); } .w64983229350s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229350s .pen1 { stroke: rgb(0,0,0); stroke-width: 19; stroke-linejoin: round; } .w64983229350s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229350s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229350s .font2 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229350s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 1 2 xA =- toward -x B:Passing .w64983229301s .brush0 { fill: rgb(255,255,255); } .w64983229301s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229301s .pen1 { stroke: rgb(0,0,0); stroke-width: 19; stroke-linejoin: round; } .w64983229301s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229301s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229301s .font2 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229301s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 1 2 xA =- toward +x C:Passing .w64983229366s .brush0 { fill: rgb(255,255,255); } .w64983229366s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229366s .pen1 { stroke: rgb(0,0,0); stroke-width: 19; stroke-linejoin: round; } .w64983229366s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229366s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229366s .font2 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229366s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 1 2 xA = toward +x D:Passing .w64983229335s .brush0 { fill: rgb(255,255,255); } .w64983229335s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229335s .pen1 { stroke: rgb(0,0,0); stroke-width: 19; stroke-linejoin: round; } .w64983229335s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229335s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229335s .font2 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229335s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 1 2 xA = toward -x
AI参考:从图中给出的信息来看，弹簧振子在t=0时刻的位置为x=A/2，初始相位为π/4。根据振动方程cos(ωt + π/4) = 0，可以得出振幅A和角频率ω的关系为A = 2√(2sin(π/4)) = 2。因此，在t时刻的位置为x = Acos(ωt) = 2cos(t)。当t=0时，位置为x=A/2，所以选项D：“Passing .w64983229335s .brush0 { fill: rgb(255,255,255); } .w64983229335s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229335s .pen1 { stroke: rgb(0,0,0); stroke-width: 19; stroke-linejoin: round; } .w64983229335s .font0 { font-weight: bold; font-size: 406px; font-family: “Times New Roman”, serif; } .w64983229335s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: “Times New Roman”, serif; } .w64983229335s .font2 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229335s .font3 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 1 2 xA = toward -x”是正确的，因此，正确答案是D。'
A: B: C: D:
AI参考:正确选项是“C: 静止的”。根据题干中的图像，货物的v-t图像与电梯一起移动，且向上的方向为正，说明货物是静止的。因此，支持力F与时间t的关系图像也是静止的。所以正确答案为C。'
A:19.9 cm B:13.9 cm C:17.9 cm D:15.9 cm
AI参考:正确答案是D：15.9 cm。根据题目中给出的信息，极星之间的角距为4.84×10^-6rad，光线波长为550nm，因此需要使用至少15.9cm的口径的天文望远镜才能区分这两个星体。因此，选项D为正确答案。'
A:480nm B:685.7nm C:533.3nm D:436.4nm
AI参考:正确答案是C：533.3nm。根据题目给出的信息，入射光波长范围为400～760nm，折射率为1.5，所以根据折射定律可以得出反射光的波长范围为400/1.5～760/1.5nm。因此反射光的波长范围为266.7～480nm，选项A、B、D均在此范围内，而C选项为533.3nm不在范围内，因此答案为C。'
A: B: C: D:
AI参考:正确答案是C。根据题目描述，给出的图形展示的是四对偏振片，每对都安装在最初无偏振的光线上。每片（用虚线表示）的偏振方向都参考了水平x轴或垂直y轴。我们需要根据通过的初始强度分数进行排名，分数最高的排在最前面。C选项描述的是“第一对偏振片的通过强度分数最高”，所以C是正确答案。'
A: B: C: D:
AI参考:正确答案是C: 运动方程就是动能定理表达的运动轨迹方程。动能定理表达了物体的运动状态变化与能量变化之间的关系，它能够确定物体的运动轨迹，即轨迹方程。因此，选项C是正确的。其他选项A、B、D都与题目无关或表述不准确。'
A:1.26mm B:1.36mm C:1.47mm D:1.50mm
AI参考:根据题意，光线以正常入射角（即垂直入射）照射到空气楔子上，光线在空气楔子的两个界面上发生干涉，形成明暗交替的干涉条纹。空气楔子的长度为L=20cm，宽度为两个干涉条纹之间的距离，即两个相邻明纹之间的距离。 由于光波长为680nm，根据干涉原理，两个相邻明纹之间的距离应该为光在空气中的波长的两倍。所以，空气楔子中两个相邻明纹之间的距离应该为 D=2 × 680nm/c = 1.5mm 因此，正确答案是D：1.5mm。"
A: B: C: D:
AI参考:正确答案是D:D选项：动量定理描述了粒子运动的动量，因此可以用速度来表达。根据动量定理，动量等于质量乘以速度，即p = mv。因此，答案为D。'
A: .w64983229380s .brush0 { fill: rgb(255,255,255); } .w64983229380s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229380s .font0 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229380s .font1 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229380s .font2 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229380s .font3 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229380s .font4 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } cos[(/)] yAtx wm =- B: .w64983229346s .brush0 { fill: rgb(255,255,255); } .w64983229346s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229346s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229346s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229346s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229346s .font3 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229346s .font4 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229346s .font5 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 0 cos{[(/)]} yAtx wmj =++ C: .w64983229313s .brush0 { fill: rgb(255,255,255); } .w64983229313s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229313s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229313s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229313s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229313s .font3 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229313s .font4 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229313s .font5 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 0 cos[(/)] yAtx wmj =-+ D: .w64983229363s .brush0 { fill: rgb(255,255,255); } .w64983229363s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229363s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229363s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229363s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229363s .font3 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229363s .font4 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229363s .font5 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; } 0 cos{[(/)]} yAtx wmj =-+
AI参考:正确答案是D：.w64983229363s .brush0 { fill: rgb(255,255,255); } .w64983229363s .pen0 { stroke: rgb(0,0,0); stroke-width: 1; stroke-linejoin: round; } .w64983229363s .font0 { font-weight: bold; font-size: 260px; font-family: "Times New Roman", serif; } .w64983229363s .font1 { font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229363s .font2 { font-style: italic; font-weight: bold; font-size: 406px; font-family: "Times New Roman", serif; } .w64983229363s .font3 { font-style: italic; font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229363s .font4 { font-weight: bold; font-size: 373px; font-family: Symbol, serif; } .w64983229363s .font5 { font-weight: bold; font-size: 76px; font-family: System, sans-serif; }因为这个问题涉及到一个正弦波，并且是在某个时刻点的位置x处的位置变化。给出的方程可以解读为y是关于t和x的函数，而且x在时间和位置上都得到了时间速度乘积的结果，并且前面的波浪号表示的是角速度。选项A和B中给出的公式在描述这个问题时出现了错误，因为公式中出现了两个波浪号和一个括号，这与题目中的描述不符。选项C中只给出了一个波浪号，而没有给出括号，这也与题目描述不符。因此，选项D中的公式是最符合题目描述的，它给出了正确的位置变化公式。所以，正确答案是D：0 cos(/) yAtx wmj =-+。'
A:错 B:对
AI参考:正确答案是B：对。根据题干中的描述，在许多重要情况下，包括弦上的波，波速完全由介质的力学性质决定。因此，可以得出结论，该题是正确的。'
A:对 B:错
AI参考:正确答案是【对】。当马拉着车前进时，马对车施加的力和车对马施加的力大小相等，方向相反，因此它们之间的相互作用力是平衡的。所以这个判断题是正确的。'
A:错 B:对
AI参考:答案是B：对。如果一个物体不受外力作用，那么它一定会处于静止状态。这是牛顿第一定律的内容，它告诉我们物体如果没有受到外力的作用，就会保持其原来的运动状态不变。因此，如果一个物体不受外力作用，那么它就会静止。所以这个判断题是正确的。'
A:错 B:对
AI参考:正确答案是B：对。瞬时速度等于该点切线的斜率。即瞬时速度与切线斜率在数值上是相等的。因此，该题正确选项为B。'
A:错 B:对
A:对 B:错
AI参考:答案是B：错。当粒子的速度为零时，加速度不一定为零。加速度是描述速度变化快慢的物理量，与速度无关。当粒子静止时，加速度可能为零，也可能不为零，取决于导致粒子静止的原因。因此，当粒子速度为零时，加速度不一定为零。'
A:对 B:错
A:对 B:错
AI参考:答案：A。引力是指任何两个物体之间的相互吸引力。'
A:错 B:对
AI参考:B:对。动摩擦力不仅可以做正功，还可以做负功。根据摩擦力做功的特点，当物体克服摩擦力做功时，摩擦力对物体做的功为负值。因此，该题正确答案是B，即动摩擦力不仅可以做正功，还可以做负功。'
A:对 B:错
AI参考:答案是B：错。在轨道空间飞船中，宇航员处于失重状态，不能用弹簧秤进行称重。失重状态是指物体受到的重力作用完全消失或大幅度减小，导致物体对支持物的压力或拉力小于或等于零，从而处于悬浮状态或飘浮状态。在这种情况下，弹簧秤无法测量宇航员的重量。因此，这个判断题是错误的。'
A:对 B:错
A:错 B:对
A:错 B:对
A:对 B:错
AI参考:答案是A，对。根据题意，汽车沿一条直路以恒定速度行驶，且这条路不对汽车做功。因此，该判断题是正确的。'
A:对 B:错
AI参考:正确答案是B：错。题目中提到的“anywhere on earth，gravity equals universal gravitation”是一个错误的观点，因为地球上的重力并不完全等于万有引力。实际上，重力是由地球的引力场产生的，而万有引力是物体间相互作用的引力，两者之间存在差异。因此，选项B是正确的。'
A:错 B:对
AI参考:答案：B:对。根据Huygens的原理，波前上的每一个点都作为球面次波的点源，经过一段时间t后，波前的新位置将是次波的位置切面。因此，选项B是正确的。'
A:对 B:错
AI参考:答案：B：错。在保守力场中，闭合路径上的力积分（即环路积分）总是等于零，因为这部分力场的力不会因路径的变化而变化。所以本题的正确答案是“错”。'
A:对 B:错
AI参考:答案是B：错。Fraunhofer衍射是在源、障碍物和屏幕之间的距离足够远，以至于我们可以考虑从源到障碍物的所有线条都是平行的，同样可以考虑到障碍物到屏幕上的给定点的所有线条都是平行的。在这种情况下，我们才可以使用Fraunhofer衍射。但是题目中没有给出这种情况，所以是错误的。'
A:对 B:错
A:错 B:对
AI参考:正确答案是B：对。位移和距离都与坐标系的原点选择有关。位移是物体位置的变化，它的大小和方向取决于参考点或原点，即与原点的选择有关。距离是两点之间的直线间隔，同样也受到原点选择的影响。因此，这个判断题是正确的。'
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