1.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: .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:"AI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。"
2.
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:2.79 m B:3.79 m C:5.79 m D:4.79m
答案:AI参考:正确选项是：B:3.79 m\n\n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。'
3.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， ）? （ ）
A:190 m B:2469 m C:3492 m D:296 m
答案:AI参考:正确答案是D：296 m。\n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。'
4.To double the total energy for a mass-spring system oscillating in SHM, by what factor must the amplitude increase? （ ）
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
答案:AI参考:正确答案是B：4。\n\n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。'
5.
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: B: C: D:
答案:AI参考:正确答案是【B】。\n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。'
6.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 （ ）
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 =+-
答案: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：\n\nA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。\n\nB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。\n\nC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。\n\nD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。\n\n因此，正确答案是C选项：“3 / 3412 xtt =++”。'
7.
The kinematic motion a particle is determined by the equation . Then its acceleration is expressed as ( ).
A: B: C: D:
答案:AI参考:正确答案是【D】\n\n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。'
8.
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 （ ）A:3.75J B:5.40J C:1.20J D:0.12J
答案:AI参考:答案：B\n推理过程：\nW=Fd=F(L-L0) (公式）\nW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\n根据题意可知：弹簧伸长量为L-L0=36-25=11cm\n所以：W=P(36-25)=5.4J。'
9.
Which of the following drawings here show physically possible refraction?( )
A: B: C: D:
答案:AI参考:正确答案是D。\n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。'
10.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:120 m B:100 m C:180 m D:150 m
答案: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。'
11.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: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 12.
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? ( )
A: B: C: D: 13.
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:47.6 m/s2 B:27.6 m/s2 C:37.6 m/s2 D:17.8 m/s2 14.
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: B: C: D: 15.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 （ ）
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 16.
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 ( )
A: B: C: D: 17.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?（ ）
A:19.9 cm B:13.9 cm C:17.9 cm D:15.9 cm 18.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 （ ）
A:480nm B:685.7nm C:533.3nm D:436.4nm 19.
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.（ ）
A: B: C: D: 20.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 （ ）
A:1.26mm B:1.36mm C:1.47mm D:1.50mm 21.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 （ ）.
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 =-+ 22.When a horse pulls a cart, the interaction force between the horse and the cart is equal in magnitude but opposite in direction. （ ）
A:对 B:错 23.A car travels at a constant speed along a straight level road, and the road does no work on the car. （ ）
A:对 B:错 24.Anywhere on earth, gravity equals universal gravitation （ ）
A:对 B:错 25.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. （ ）
A:错 B:对 26.In many important situations including waves on a string, the wave speed is determined entirely by the mechanical properties of the medium. （ ）
A:错误 B:正确 27.If the external force on the object is zero, the object must be at rest. （ ）
A:错误 B:正确 28.The instantaneous velocity is equal to the slope of the tangent line at that point. （ ）
A:错误 B:正确 29.When the particle’s velocity is zero, the acceleration must also be zero. （ ）
A:正确 B:错误 30.The average speed is equal to the magnitude of the average velocity. （ ）
A:正确 B:错误 31.Gravitation refers to the mutual attraction between any two objects. （ ）
A:正确 B:错误 32.Kinetic friction force can not only do positive work but also do negative work. （ ）
A:错误 B:正确 33.In an orbiting spacecraft, the astronaut is weightless and cannot be weighed with a spring scale. （ ）
A:正确 B:错误 34.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. （ ）
A:错 B:对 35.The direction of polarization of an electromagnetic wave is defined to be the direction of the electric-field vector. （ ）
A:错误 B:正确 36.The loop integral of the force in the conservative force field may not be zero. （ ）
A:正确 B:错误 37.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. （ ）
A:正确 B:错误 38.An electromagnetic wave is a transverse wave; the fluctuating electric and magnetic fields are perpendicular to each other and to the direction of propagation. （ ）
A:正确 B:错误 39.Both the displacement and distance are related to the selection of the origin of coordinate. （ ）
A:错误 B:正确 40.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? （ ）
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;
