2015届中考物理核心考点专项训练:专题06 作图、简答题攻略(原卷版)

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专题06 静电场中的点电荷模型-高考物理模型系列之对象模型(原卷版)

专题06 静电场中的点电荷模型-高考物理模型系列之对象模型(原卷版)

模型界定点电荷是一种理想化模型,主要特征是带电体的形状与大小可以忽略.本模型中涉及到的问题有点电荷的平衡、点电荷的场强与电势、电场的迭加、带电粒子在点电荷电场中的运动等.模型破解1.点电荷之间的相互作用力(i)库仑定律真空中两个静止点电荷的相互作用力,与它们的电荷量的乘积成正比,与它们的距离的二次方成反比,作用的方向在它们的连线上.(ii)适用条件(I)真空中,(II)点电荷.①点电荷在空气中发生相互作用,也可用库仑定律来处理.②对于均匀带电的绝缘球体,可视为电荷集中了球心的点电荷,r为球心的距离.③对于带电金属球,由于球内的自由电荷可以自由移,要考虑静电力对电荷分布的影响,在距离不大时,等效电荷中心与球心不重合,r是等效电荷中心间的距离,而非球心的间距.④库仑力在r=10-15~10-11 m的范围内均有效,所以不要根据公式推出错误的结论:当r→0时,F→∞,其实,在这样的条件下,两个带电体也已经不能再看做点电荷.(iii)电荷分配接触带电体分享后的电荷分配与带电体的形状与大小有关.对于大小相同的球体将总电荷量平分.例1.三个相同的金属小球1、2、3分别置于绝缘支架上,各球之间的距离远大于小球的直径。

球1的带电量为q,球2的带电量为nq,球3不带电且离球1和球2很远,此时球1、2之间作用力的大小为F。

现使球3先与球2接触,再与球1接触,然后将球3移至远处,此时1、2之间作用力的大小仍为F,方向不变。

由此可知A.n=3 B.n=4 C.n=5 D.n=6例2.有两个半径为r的带电金属球,球心相距l(l=4r),对于它们之间的静电作用力的说法正确的是(设每次各球所带电荷量的绝对值均相等)A.在带同种电荷时大于带异种电荷时的作用力B.在带异种电荷时大于带同种电荷时的作用力C.在都带负电荷时大于都带正电荷时的作用力D.大小与带电性质无关,只取决于所带电荷量模型演练1.两个分别带有电荷量Q -和+3Q 的相同金属小球(均可视为点电荷),固定在相距为r 的两处,它们间库仑力的大小为F 。

专题06正多边形和圆(3个考点六大类型)(原卷版)

专题06正多边形和圆(3个考点六大类型)(原卷版)

专题06 正多边形和圆(3个考点六大类型)【题型1 正多边形与圆求角度】【题型2正多边形与圆求线段长度】【题型3正多边形与圆求半径】【题型4正多边形与圆求面积】【题型5正多边形与圆求周长】【题型6正多边形与直角坐标系综合】【题型1 正多边形与圆求角度】1.(2023•青羊区校级模拟)如图,正六边形ABCDEF内接于⊙O,∠ADB的度数是()A.20°B.30°C.45°D.60°2.(2023•荷塘区模拟)如图,以正五边形ABCDE的顶点A为圆心作⊙A分别与边AE、AB交于点F、G,点P是劣弧FG上一点,连接PF、PG,则∠FPG 的度数为()A.116°B.120°C.124°D.126°3.(2023•惠水县一模)如图,边长相等的正五边形、正六边形的一边重合,则∠1的度数为()A.10°B.12°C.20°D.22°4.(2023•渌口区二模)如图,正五边形ABCDE内接于⊙O,点F在弧AE上.若∠CDF=96°,则∠FCD的大小为()A.38°B.42°C.48°D.58°5.(2022秋•曲周县期末)已知:如图,四边形ABCD是⊙O的内接正方形,点P是劣弧上不同于点C的任意一点,则∠BPC的度数等于()A.45°B.60°C.35°D.55°6.(2023•新市区校级一模)如图,⊙O与正五边形ABCDE的边AB、DE分别相切于点B、D,则劣弧所对的圆心角∠BOD的大小为()A.150°B.144°C.135°D.120°7.(2023•泰兴市二模)如图,正六边形ABCDEF与⊙O相切于点C、F,则∠COF=°.8.(2023•南关区校级模拟)如图摆放着正五边形ABCDE和正△EFG,其中点A、B、F在同一直线上,EG∥BF,则∠DEG的度数是.9.(2023•天山区校级一模)如图,正五边形ABCDE内接于⊙O,则∠DAC的度数为.10.(2023•霍林郭勒市校级三模)如图,正五边形ABCDE内接于⊙O,则∠ADE 的度数是.11.(2023•陇南模拟)如图,正六边形ABCDEF内接于⊙O,连接BD,则∠CBD的度数是.12.(2022秋•南浔区期末)已知正五边形ABCDE内接于⊙O,连接BD,则∠ABD的度数是.13.(2023•子洲县校级一模)如图,在正六边形ABCDEF中,延长AB交EC 的延长线于点G,则∠G的度数为.【题型2正多边形与圆求线段长度】14.(2023春•鼓楼区校级期中)如图,A、B、C、D为一个正多边形的顶点,若∠ADB=15°,则该正多边形的边数为()A.9B.10C.11D.12 15.(2022秋•烟台期末)如图,正六边形ABCDEF内接于⊙O,若⊙O的周长等于6π,则正六边形的边长为()A.B.3C.D.16.(2022•成都)如图,正六边形ABCDEF内接于⊙O,若⊙O的周长等于6π,则正六边形的边长为()A.B.C.3D.2 17.(2023•苏州二模)如图,正六边形ABCDEF内接于⊙O,⊙O的半径为1,过O作OM垂直AB,交AB于点M,则OM的长为.18.(2022秋•荔湾区校级期末)如图,已知正六边形的边心距OG为,则它的边长AB为.19.(2022秋•甘井子区校级期末)如图,在拧开一个边长为a的正六角形螺帽时,扳手张开的开口,则边长a为mm.【题型3正多边形与圆求半径】20.(2022秋•铜山区期中)如图,圆内接正六边形ABCDEF的周长为12cm,则该正六边形的内切圆半径为()A.cm B.2cm C.2cm D.cm21.(2022秋•红桥区期末)若一个正六边形的边长为2,则其外接圆与内切圆的半径分别为()A.2,1B.2,C.,2D.,3 22.(2022秋•巩义市期末)如图,已知⊙O的内接正方形ABCD的边长为1,则⊙O的半径为()A.B.C.1D.23.(2022秋•东丽区期末)正方形边长为4,则其外接圆半径为()A.2B.C.4D.24.(2022秋•开封期末)正六边形ABCDEF内接于⊙O,正六边形的周长是24,则⊙O的半径是.【题型4正多边形与圆求面积】25.(2023•南山区二模)刘徽在《九章算术注》中首创“割圆术”,利用圆的内接正多边形来确定圆周率,开创了中国数学发展史上圆周率研究的新纪元.某同学在学习“割圆术”的过程中,作了一个如图所示的圆内接正八边形.若⊙O的半径为1,则这个圆内接正八边形的面积为()A.πB.2πC.D.26.(2023•济源一模)如图,正六边形ABCDEF,A(﹣2,0),D(2,0),点P从点A出发,沿A→B→C→D→E→F→A以每秒1个单位长度的速度运动,当运动到第2023秒时,△AOP的面积为()A.B.C.D.1 27.(2023•大冶市一模)如图,有一个亭子,它的地基是边长为4m的正六边形,则地基的面积为()A.4m2B.12m2C.24m2D.24m2 28.(2023•宁江区二模)如图,以直角三角形的三边为边向外作正五边形,若S1=13,S2=5,则S3的面积为()A.12B.25C.8D.18 29.(2023•高碑店市模拟)如图,在一张正六边形纸片中剪下两个全等的直角三角形(阴影部分),拼成一个四边形,若拼成的四边形的面积为2,则纸片的剩余部分拼成的五边形的面积为()A.5B.6C.8D.10 30.(2023•惠山区校级模拟)如图,面积为6的正六边形ABCDEF中,点M,N分别为边BC,EF上的动点,则阴影部分面积为()A.2B.3C.4D.5 31.(2023•桓台县一模)如图,正六边形ABCDEF内接于⊙O,若⊙O的周长等于6π,则正六边形的面积为()A.B.C.D.32.(2023•温州二模)如图,菱形花坛ABCD的边长为9米,∠B=60°,其中由两个正六边形组成的部分种花,则种花部分的面积为米2.33.(2022秋•碑林区校级期末)如图,正六边形ABCDEF中,对角线BE长为4,则△BDE的面积为.【题型5正多边形与圆求周长】34.(2023春•余姚市期中)一个边长为1的正多边形的每个外角的度数是36°,则这个正多边形的周长是()A.1B.10C.5D.35.(2022秋•开封期末)一个正多边形的边长是3,从一个顶点可以引出4条对角线,则这个正多边形的周长是()A.12B.15C.18D.21 36.(2022秋•北辰区校级期末)边心距为3的正六边形的周长为()A.18B.C.D.37.(2022秋•南沙区校级期末)已知有一个亭子,它的地基是半径为4m的正六边形,则此地基的周长为()A.12m B.12m C.24m D.24m 38.(2023春•和平区校级月考)如图,已知正六边形的边心距为3,则它的周长是()A.6B.12C.D.39.(2022•新昌县校级模拟)一个正多边形的边长为2,每个内角为135°,则这个多边形的周长是()A.8B.14C.16D.20 40.(2023•钦州一模)如图,若一个正六边形的对角线AB的长为10,则正六边形的周长()A.5B.6C.30D.36 41.(2023•鼓楼区模拟)下列图形中,正多边形内接于半径相等的圆,其中正多边形周长最小的是()A.B.C.D.42.(2022秋•河西区期末)六个带30°角的直角三角板拼成一个正六边形,直角三角板的最短边为10,求中间正六边形的周长.43.(2023•苏州模拟)已知正六边形的半径为,则它的周长=.44.(2023•青海模拟)等宽曲线是这样的一种几何图形,它们在任何方向上的直径(或称宽度)都是相等的.如图,分别以等边△ABC的三个顶点为圆心,边长为半径画弧则弧AB,弧BC弧AC组成的封闭图形就是“莱洛三角形”.莱洛三角形是“等宽曲线”,用莱洛三角形做横断面的滚子,能使载重物水平移动而不至于上下颠簸,若AB=3,则此“莱诺三角形”的周长为.【题型6正多边形与直角坐标系综合】45.(2023•山西)蜂巢结构精巧,其巢房横截面的形状均为正六边形.如图是部分巢房的横截面图,图中7个全等的正六边形不重叠且无缝隙,将其放在平面直角坐标系中,点P,Q,M均为正六边形的顶点.若点P,Q的坐标分别为,(0,﹣3),则点M的坐标为()A.(3,﹣2)B.(3,2)C.(2,﹣3)D.(﹣2,﹣3)46.(2023•辉县市二模)我们知道,五边形具有不稳定性.正五边形OABCD 在平面直角坐标系中的位置如图(1)所示,A(﹣2,0).固定边AO,将正五边形向右推,使点A,B,C共线,且点C落在y轴上,如图(2)所示,则此时点D的坐标为()A.B.C.(1,2)D.47.(2023•宝应县二模)三个能够重合的正六边形的位置如图,已知A点的坐标是,则B点的坐标是.。

专题06 光学作图(原卷版)

专题06 光学作图(原卷版)

专题6:光学作图类型一:光的直线传播1.(2022•赤峰中考)如图所示,在路灯(A点表示)的照射下,地面上出现了小树BC的影子BD,请根据光的直线传播知识画图确定点D的位置。

2.如图所示,请根据两人影子的位置画出灯泡S的位置。

3.如图,请画出蜡烛AB经小孔所成像的光路及其在光屏MN上所成的像A’B'。

类型二:光的反射4.(2022•黔西南州中考)阳光与水平面成60°角射向地面,用平面镜使阳光竖直射入井底,在图中画出平面镜的位置,并标明反射角的度数。

5.(2022•梧州中考)如图,小玲利用一块平面镜,将正午时分直射的太阳光引入一根水平管道内,请在图中画出平面镜的位置。

6.(2021•娄底中考)画出经图示平面镜组(两镜面互相垂直)反射后的反射光线。

类型三:光的折射7.(2022•广州中考)如图,一条光线垂直界面AC进入玻璃砖后,在界面AB上只发生反射,在图中画出该光线经界面AB反射和从界面BC离开玻璃砖后的光线。

8.(2020•黔南州中考)如图所示,一束光射向玻璃砖并穿过玻璃砖,画出这束光进入玻璃和离开玻璃后的光线。

类型四:光的反射、折射综合作图9.(2022•巴中中考)如图中已标出了反射光线OB,请画出对应的入射光线AO和折射光线的大致方向OC。

10.(2021•鄂州中考)如图,光源S发出的一束光经墙上的平面镜反射后,射入游泳池中,刚好被正在游泳的小明看到。

请完成光路图。

11.如图,一束光线从水中斜射到空气时发生折射,OB为折射光线,请大致作出入射光线和对应的反射光线。

类型五:平面镜成像特点12.(2022•宿迁)在图中根据平面镜成像特点作出物体AB在平面镜中所成的像A'B'。

13.如图所示,玻璃板与桌面倾斜,A点表示小明的眼睛,请画出烛焰最高点S发出的光经玻璃板后进入人眼A点的光路图。

14.(2021•聊城中考)如图所示,从A点出发的一条光线,经平面镜反射后,其反射光线恰好经过B点,请作出这条入射光线并完成光路图。

2015广东物理中考 专题复习作图

2015广东物理中考  专题复习作图

二、滑轮组
例4:[2010.广东]如图13所示,某人站在A处用一 根绳子和两个滑轮提起物体B,画出最省力的绕线。
如图:
方法:奇动偶定(F=G/n)
中考典例精析
电学作图题专题
一、 电路图和实物图
例1:[2010﹒广东] 在虚线框内画出图12所示的实物图的电路图
图12
方法指导:根据要求明确电路性质,并联找准“分、合 点”,电表的正负接线柱、量程选择要当心,滑动变阻器 一上一下接!
3.折射----- 找准法线位置;分清两角大小 透镜------ 找“特殊”
【光路可逆】
作图注意事项:
1. 铅笔直尺,拿在手中
2. 熟悉规律,特殊别忘
3. 实线虚线,牢记心中 4. 带上箭头,一定记清
力学作图题专题
一、力的示意图
是一种表示力的方法,即用一根带有箭头的线段把 力的大小、方向、作用点都表示出来。具体步骤: (1) 明确力应该画在谁身上;(作用点在受力物体 上) (2) 明确力的方向;(一般情况下,我们所接触到 的力有:重力G,方向始终竖直向下;支持力F支, 方向垂直接触面向外;压力F压,方向垂直接触面向 里;拉力F拉,方向延绳子向外;摩擦力f ,方向与 运动或想运动的方向相反。) (3) 明确表示力的字母;(如上所示)
解题技巧:
1.找发光点的像点 2.把像点与反射光线(或入射光射)照射点连
线,与镜面的交点为入射点
3,连入射光线和反射光线
中考典例精析
三.光的折射
1.利用光的折射规律
例6:[2009.广东]如图9所示,AO表示从空气斜 射向玻璃砖上表面的一束光,请大致画出这束 光在玻璃砖中的折射光线。
如图:
解题技巧:找准法线位置;分清两角大小

中考物理实验专题06 探究平面镜成像的特点(考点精讲+练习学生版+解析版)

中考物理实验专题06 探究平面镜成像的特点(考点精讲+练习学生版+解析版)

实验06 探究平面镜成像的特点考点精讲【设计与进行实验】1.2.主要实验器材:玻璃板、刻度尺、两根完全相同的蜡烛、白纸等;刻度尺的作用是测量像与物到平面镜的距离3.实验装置:用玻璃板代替平面镜,为了便于找到像的位置;让相同的蜡烛(未点燃)与点燃的蜡烛的像重合,找到像的位置、比较物和像大小关系;4.5.生这个的原因是玻璃板有一定的厚度,通过玻璃板的前后两个面各形成一个像,产生重影;6.实验中应选择茶色玻璃板.因为透明玻璃板透光性较强,反光性较弱,而这个实验对透光性有要求,对反光性也有要求,所以应选用透光性不如透明玻璃板而反光性强于透明玻璃板的茶色玻璃板.6.实验中像的大小始终等于物体大小,通过肉眼看见“近大远小”,这与视角有关;7.实验中无论平面镜多小,都能使物体形成一个完整的与物体等大的像(物体上反射的光线总有射向平面镜的);8.方向倾斜,则蜡烛的像总在未点燃蜡烛的上方偏高处;若玻璃板向未点燃蜡烛的方向倾斜,则蜡烛的像总在未点燃蜡烛的下方偏低处;9.刻度尺的作用:测量像与物到玻璃板的距离;10.观察像时眼睛的位置:与物同侧;用光屏代替未点燃的蜡烛,看在光屏上是否能承接蜡烛成的像;12.本实验的目的在于研究蜡烛A的像是否与蜡烛A的大小相同,如果将蜡烛B也点燃,则蜡烛B也会产生一个像,会对实验产生干扰;并且如果玻璃板两侧蜡烛都点燃的话,就没有黑暗和明亮的对比,不利于观察蜡烛A的像的准确位置.13.实验中移去蜡烛B,并在蜡烛B所在的位置上放一光屏,则光屏上不能承接到蜡烛A的像,所以平面镜所成的像是虚像.12.多次测量的目的:多次改变蜡烛和玻璃板之间的间距,使结论更具有普遍性;13.物体移动时,像移动方向、距离、速度的判断;【交流与反思】14. ①蜡烛没有垂直放置;①后支蜡烛与前支蜡烛在玻璃板中的像没有完全重合;①玻璃板太厚;15.等、灯泡比蜡烛亮,实验效果更明显、灯泡可反复使用;16.(1)将桌面上的白纸换成方格纸的好处是方便比较蜡烛A和像到平面镜的距离.(2)观察像的时候,眼睛的位置应与蜡烛A同侧.因为平面镜成像的原理是光的反射,且只有当光进入人眼时,人眼才能看到像.(3)实验中,测得的蜡烛A和像到玻璃板的距离不相等,则可能的原因有:①蜡烛B与蜡烛A 所成的像没有完全重合;①玻璃板太厚.实验结论:物体在平面镜中成的是正立的虚像;像和物体的大小相等;像和物体到镜面的距离相等;像和物体的连线与镜面垂直。

期末考点串讲 专题06 完形填空专练(原卷版)

期末考点串讲 专题06 完形填空专练(原卷版)

专题06 完形填空专练1.Do you know anything about the invention of the bar code (条形码)?A small food store owner found it was (1)to keep records of the product information.In 1948,he asked the Drexel Institute of Technology to solve this (2).Bernard Silver,a graduate student,was interested.He and his friend Norman Joseph Woodland (3)to work on it.Soon,they invented their first working system (系统).The system did work (4),but it was very expensive and sometimes the system didn't work well.If the invention was to become (5)in stores,the problems had to be solved.Finally,Woodland solved (6).The patent (专利权)for the bar code system was (7)for by Silver and Woodland in 1949,but the patent was not given until 1952.(8)this patent was given,the system was still not popular among store owners.In 1970,a business named Logicon Inc.(9)the Universal Grocery Products Identification Code (食品工业统一码).Marsh's Supermarket in Troy was the first store to (10)this bar code reading system.It has become very popular ever since,and now it's used in all types of stores all over the world.1.A.easy B.difficult C.interesting D.boring2.A.plan B.problem C.project D.doubt3.A.started B.continued C.refused D.failed4.A.at first B.for example C.on time D.in person5.A.lively B.cheap C.direct D.popular6.A.it B.him C.her D.them7.A.asked B.offered C.made D.divided8.A.Unless B.Although C.If D.Since9.A.found B.mentioned C.invented D.remained10.A.give up B.put up C.set up D.clean up2.Now tea and coffee are very popular around the world.However,several hundred years ago,some people in the West did not like coffee or tea.They were (1)to drink them because they thought coffee or tea could kill a person.Once a king wanted to find out (2)or not it is true.At that time there were two brothers in prison(监狱).The king would (3)them in a few days because they did something terrible.The king said "I shall let them live but they must drink coffee or tea to the end of their(4).One brother must drink coffee and(5)must drink tea every day.And the two brothers(6)the king's words.They(7)lived many years.At last,the elder brother(8)when he was eighty three years old.The younger one passed away a few years(9).After that,people (10)that coffee and tea were not bad for man.Gradually,more and more people began to drink them.(1)A.happy B.afraid C.rich D.glad(2)A.when B.what C.whether D.if(3)A.kill B.teach C.lay D.trade(4)A.lives B.job C.talks D.traditions(5)A.one B.other C.another D.the other(6)A.heard B.followed C.listened D.noticed(7)A.both B.each C.also D.all(8)A.killed B.lived C.died D.kept(9)A.ago B.later C.old D.before(10)A.shouted B.spoke C.kept D.knew3.A new law (法律)in New York allows people to bring their dogs to restaurants.Some people (1)eating with dogs is great.They argue that it's good for dogs.They say owners don't have to leave their pets home alone or in cars while they eat out.But some people are (2)about eating next to dogs.They say dog hair can create unclean conditions.Also,dogs can annoy (烦扰)customers (3)barking (吠叫)or making a mess.Should dogs be (4)in restaurants?Here is what two students think.YES!As long as dogs are well﹣behaved (很乖的)and clean,there's no (5)why they shouldn't be allowed in restaurants with their owners.When restaurants allow dogs,people can spend more time with their (6).That will make them both happier.If someone doesn't want to eat near dogs,they can eat in the indoor part of the restaurant.(7)they can go to a restaurant that doesn't allow dogs.Victoria Gonzalez,North CarolinaNO!Dogs (8)be allowed in restaurants.They can cause health problems.Some people are allergic (过敏的)to dogs,so being around dogs could be (9)for them.Also,some dogs could annoy customers by jumping on them or stealing their food.Some dogs might even hurt customers.If that (10),restaurants may end up losing customers and money.Josh Cramer,Wisconsin 1.A.hope B.think C.hear D.see2.A.happy B.sure C.worried D.honest3.A.by B.in C.on D.with4.A.allowed B.eaten C.drawn D.hidden5.A.time B.place C.problem D.reason6.A.kids B.pets C.customers D.parents7.A.But B.If C.Or D.So8.A.would B.wouldn't C.should D.shouldn't9.A.safe B.easy C.dangerous D.difficult10.A.happens B.remains C.fails D.stops.4."I don't like my parents.They always tell me I should do this,and should not do that. It sometimes makes me(1)," said Zhang Hua,a middle school student in Guangzhou.Do you have the(2)problem?Perhaps your parents had the same problem when they were your age long ago.Why does it seem that some parents are not so friendly in their children's eyes?One of the biggest things is(3)someone becomes a parent,he or she likes worrying about things.They worry about everything about you,from the time you were born.They worry about your(4)of friends,the food you eat,your work at school,how much seep you get,etc.All these things are part of your life.They want you to grow up(5)and happily. So how can you(6)things easier on yourself?Just make sure your parents know what you're doing.Get them to know your friends.Phone if you stay somewhere else.Say sorry to them when you make mistakes.Take responsibility (责任)for what you have done.Talk about your (7)with them.They may talk about theirs with you.Most of all,try to(8)why your parents do this or do that.They are still (9)being parents and need help you can give them.Someday,when you become a parent,they may be able to help you how to(10)your children.(1)A.thankful B.angry C.happy D.sad(2)A.serious B.difficult C.different D.same(3)A.when B.though C.because D.unless(4)munication ment C.choice D.decision(5)A.healthily B.hardly C.strongly D.easily(6)A.have B.find C.try D.make(7)A.homework B.meals C.ideas D.games(8)A.think of B.think about C.talk of D.talk about(9)A.moving B.practicing C.helping D.working(10)A.take the place of e up with C.take away from D.get on with5.The pyramids (金字塔)have been lying on the lower west bank of the Nile for nearly 4,000 years.They are not only the tombs (坟墓)for the pharaohs (法老),but also the treasures (1)all human beings.We call them jinzita because of their shape(2)looks like the Chinese character "jin"!Until now,there have still been many mysteries waiting to be solved. The largest pyramid is the Pyramid of Khufu:756 feet long on each side and 481 feet tall.There are about 2.3 million blocks.How the ancient builders managed(3)such a large structure has never been fully answered,but the effort clearly (4)brains and brawn (体力).If 7﹣ton trucks are used to pick up all the blocks,we need about 978,286 trucks!(5)there were enough workers,they couldn't carry the heavy blocks.Some people think they (6)put the woody stick under the blocks as the wheel.But(7)needs a lot of wood. (8)number of trees can't meet the requirement.Others hold an opinion that they used the water transport (水上运输).However,with no equipment (设备)to load (装载)or unload (卸载)the blocks,it seems(9)than the first idea.In fact,all the blocks must(10)from the east of the Nile.So the mystery remains a mystery.(1)A.with B.of C.for D.on(2)A.who B.what C.which D.where(3)A.build B.building C.to build D.built(4)A.require B.required C.was requiring D.will require(5)A.Because B.Unless C.If D.Though(6)A.need B.should C.must D.might(7)A.it B.its C.it's D.itself(8)A.A B.An C. / D.The(9)A.difficult B.difficultly C.more difficult D.the most difficult(10)A.carry B.carries C.carried D.be carried6.Once there lived a deer that walked with his head high and his long antlers (鹿角)showed natural grace (优美).He treated all the other animals well and even the lion(1)him. One day,a group of traders lost their(2)in the forest.They didn't know what to do,feeling so worried.The deer walked to them,told them to(3)him and led them out of the forest.The traders went to the king and told him about the wonderful deer and his (4).However,the king paid no attention to the words.He just heard that there was a deer with the most beautiful antlers in the forest.Then,he decided to go and hunt (猎杀)the deer (5).When he went into the forest with his soldiers,he said,"All of you should not shoot at him.He belongs to me." The king tried to shoot the deer many times,(6)he didn't succeed.As the king(7)the dear,he went deep into the forest.(8)the king fell into a deep hole and cried for help.Without a second thought the deer ran to the hole and lowered his strong antlers.The king held on to them and the deer pulled him out.Then,the deer let the king sit on his back and took him back to his soldiers.The king was so(9)to the deer that he finally invited the deer to his palace as a friend.As we can see,if we can learn to help our enemies when they are(10),we are pleased to win friends for life.(1)A.hurt B.refused C.respected cated(2)A.way B.weight C.voice D.mind(3)A.teach B.remember C.follow D.catch(4)A.kindness B.worry C.happiness D.danger(5)A.at first B.at once C.by mistake D.in order(6)A.but B.or C.so D.unless(7)A.talked of B.heard of C.ran after D.looked after(8)A.Suddenly B.Angrily C.Gradually D.Luckily(9)A.friendly B.thankful C.harmful D.polite(10)A.sad B.happy fortable D.helpless7.If you were ninety years old,what would you plan to do?Few people want to have new challenges (挑战)(1)that age. However,an old man named Jing Kui did something that surprised a lot of people.As a man of 93,he met a challenge.One day,(2)film director came to him and asked whether he wanted to act in his movie. "What can I do in the movie?" asked the old man. "You've been a barber (理发师).I believe you're the right man for(3)movie The Barber."The old man read the script (剧本)before accepting the invitation. (4)he knew the story well,he still needed to keep all the words in mind. (5)big the challenge was! He finally made it and took home a silver cup for a special acting prize. The movie also(6)both national and international prizes.Jing became a barber when he was young.He loved the job,so he practiced hard(7) a better one.In his eighties,he was still doing the same job.That was why he(8)by the film director.While the film was being made,the director had his worries because he didn't know(9)Mr Jing could keep it going.Al last,when the filming was done,the director was really pleased.Jing(10)solved all his problems!Now Jing set a world record as being a 93﹣year﹣old actor star who had never acted before!(1)A.from B.of C.at D.on(2)A.the B. / C.a D.an(3)A.my B.I C.me D.mine(4)A.Unless B.Though C.Since D.Until(5)A.How B.What C.What a D.What an(6)A.will win B.win C.wins D.won(7)A.be B.being C.to be D.been(8)A.invites B.invited C.is invited D.was invited(9)A.that B.if C.where D.when(10)A.success B.succeed C.successful D.successfully8.A long time ago,there was a huge apple tree.A little boy loved to come(1)play around it every day.He climbed to the tree top,(2)the apples or played under thetree.He loved the tree and the tree loved to play with him.Time went by.The little boy had(3)and he no longer played around the tree.One day,the boy came back to the tree and(4)sad. "Come and play with me," the tree asked the boy."I am no longer a kid,I do not play around trees anymore," the boy(5)."I want toys.I need (6)to buy them." "Sorry,but I don't have money.But you can pick all my apples and(7)them.So,you will have money." The boy was so (8).He picked all the apples on the tree and left happily.The boy didn't come back (9)he picked the apples.The tree was(10).One day,the boy(11)and the tree was so excited,"Come and play with me," the tree said. "I don't have time to play.I have to work for my family.We need a(12).Can you help me?" "Sorry,but I don't have a house.But you can (13)my branches to build your house." So the boy cut all the branches of the tree and left(14).The tree was glad to see him full of joy but the boy didn't appear.Since then the tree felt again (15)and sad.(1)A.but B.and C.or D.so(2)A.ate B.destroyed C.played D.loved(3)in down B.stood C.grown up D.put down(4)A.fell B.saw C.sounded D.looked(5)A.asked B.replied C.told ughed(6)A.money B.wood C.branches D.apples(7)A.cook B.cat C.sell D.offer(8)A.surprised B.excited C.nervous D.sorry(9)A.if B.before C.when D.after(10)A.sad B.afraid C.pleased D.angry(11)A.disappeared B.left C.moved D.returned(12)A.kitchen B.yard C.home D.house(13)A.take off B.pick C.cut off D.plant(14)A.happily B.seriously C.slowly D.silently(15)A.alone B.lonely C.proud D.satisfied9.A young man wanted to find a job after finishing school.One day,he went to a big companyfor it.There were six young people that day(1)they only wanted one.The interview was very(2).It was only a few minutes' short talk.Then the six young men all went (3).On the morning of the third day,the young man got a text message.It (4),"We are sorry to tell you that you cannot (5)in our company."The young man (6)very sorry,but he answered politely,"Thank you all the same." in the text message,Later that afternoon,the young man got (7)text message saying,"We are glad to tell you that you (8)be one of us!"The young man didn't know(9).People in the company told him,"That's because of the same message sent to you six in the morning.But only you said,Thank you. That was the (10)test,and only you gave the right answer."When you feel disappointed,do not forget to say "Thank you" to the one who disappoints you.(1)A.and B.but C.or D.so(2)A.interesting B.exciting C.hard D.easy(3)A.home B.house C.family D.room(4)A.told B.talked C.said D.spoke(5)A.stay B.work C.play D.study(6)A.looked B.smelt C.tasted D.felt(7)A.another B.other C.the other D.others(8)A.must B.have to C.can D.would(9)A.when B.why C.what D.how(10)A.only B.just C.true D.real10.Living in a new country gives me many surprises.The first surprise was the way that the US people(1).One day I saw someone was having a public speech in a square.I thought it would be a(2)speech.But I soon found it became a kind of entertainment show.The speaker told the listeners to protect the environment with humorous words.Later he said some people's behavior didn't go with their(3).He took the example of Taylor Swift's song We Are Never Ever Getting Back Together.He said that since Swift doesn't want to be with the boy any more,she doesn't need to speak it aloud,she doesn't need to sing(4)she still keeps in touch with that guy.It sounds like she is a hypocrite(伪君子).Then he sang the song in a(5)way.The listeners laughed out loudly.I felt a little (6)because Swift is my favorite star.I couldn't understand why they(7)Swift.As time goes on,I find many US people make fun of others,(8)they don't mean to hurt them.They do that to show closeness and humor.And people who are laughed at(9)get angry.Now I understand the speaker(10).Now I've got used to the way the US people speak.It's easy to find culture shock when you're in a new place.But everyone should learn to understand different cultures and customs.(1)A.talk B.speak C.sing D.teach(2)A.lovely B.funny C.serious D.polite(3)A.words B.lessons C.listeners D.speakers(4)A.although B.when C.if D.unless(5)A.simple B.funny C.active D.soft(6)A.happy B.satisfied C.angry D.nervous(7)A.worried about B.talked about C.laughed at D.cared for(8)A.so B.and C.or D.but(9)A.seldom B.always C.easily D.often(10)A.at the school B.in the square C.at the concert D.in the park。

初三物理中考复习专题《作图与简答》

初三物理中考复习专题《作图与简答》

初三物理中考复习专题:《作图与简答》班级______________姓名_____________座号_________【作图专题】1、考查光学作图(1)考查透镜的三条特殊光线:平行入焦点出;焦点入平行出;过光心路不变。

(2)考查平面镜成像:①等大等距,连线垂直。

②反射光线的反向延长线经过像点。

(3)光学规律:反射定律与折射定律。

例1、完成透镜的光路图。

例2、根据图中光线的传播方向,在虚线方框中添上适当的透镜。

例3、画出一束光经空气射向玻璃砖,请依次画出两次折射的光路图。

例4、如图所示,AB 、CD 是某一点光源发出的两条光线的反射光线,请画出此点光源S 及光源的像S ’。

例5、在图12中,完成光线从左边射向凸透镜折射后,再射向凹透镜折射后的光路。

2、考查力的示意图(1)重力:外形规则、质在均匀的物体的作用点在几何中心上,方向竖直向下,用字母G 表示;(2)弹力:①压力:作用点在受压物体表面上,方向垂直与物体表面,指向受压面;②支持力与压力相似;③绳子的拉力:延绳子收缩的方向;(3)摩擦力:方向与相对运动(趋势)方向相反。

例6、图甲所示,一位同学在用力推箱子,但没推动,请在图乙中画出箱子的受力示意图。

例7、如图,车减速前进,画出悬挂在车厢内的物体A 所受力的示意图。

例1 例 2 例3 例4 例 5 A C BD 例6甲 例6乙 例7作力臂分三步:一找点(支点),二找线(力的作用线,可用直尺与力的线重合,以判断是否延长),三作垂线段(垂线段即是力臂)。

例8、如图所示的人前臂可以看成杠杆,图中O 为支点,当肱二头肌将重力为40N 的铅球托起时,画出人的手臂受到的阻力F 2的示意图和阻力臂L 2。

例9、在图中画出使杠杆OA 平衡时最小动力F 1的示意图和阻力F 2的力臂。

4、考查滑轮组的组装(1)绳子的段数n=G/F (进位取整),动滑轮的个数N=n/2(直接取整,不进位)。

(2)绳子缠绕方法:奇动偶定。

中考物理考点专题训练:专题06 两种电荷(含解析)

中考物理考点专题训练:专题06 两种电荷(含解析)

专题06 两种电荷一、摩擦起电1、定义:用摩擦的方法使物体带电叫做摩擦起电。

2、实质:电子从一个物体转移到另一个物体上(电子的转移)。

3、特点:互相摩擦的两个物体,必然带上等量的异种电荷。

一些物体被摩擦后能够带上电荷,因而能吸引轻小物体。

这种使物体带电的现象,就是摩擦起电现象。

二、电荷间的相互作用(1)用绸子摩擦的玻璃棒带的电荷叫正电荷;(2)把用毛皮摩擦过的橡胶棒带的电荷叫负电荷;(3)基本性质:同种电荷相互排斥,异种电荷相互吸引;三、验电器的原理和作用 (1)用途:用来检验物体是否带电;(2)原理:利用同种电荷相互排斥;四、导体和绝缘体(1)善于导电的物体叫导体;如:金属、人体、大地、酸碱盐溶液; (2)不善于导电的物体叫绝缘体,如:橡胶、玻璃、塑料等;(3)金属导体靠自由电子导电,酸碱盐水溶液靠正负离子导电;(4)导体和绝缘体在一定条件下可以相互转换。

五、原子的核式结构模型原子由原子核和核外电子组成,原子核位于原子的中心,原子核的半径比原子小得多,原子核的质量比电子大得多,原子核带正电,电子带负电,电子在原子核的引力作用下,在核外绕核运动。

典型例题用一根带负电的橡胶棒靠近一轻质小球,发现两者相互排斥,由此可判定()A.小球一定带负电B.小球一定带正电点C.小球一定不带电D.小球可能带负电,也可能不带电解析:电荷间的相互作用是:同种电荷相互排斥;异种电荷相互吸引。

用一根带负电的橡胶棒靠近一轻质小球,发现两者相互排斥,由此可判定小球一定带负电。

故选A答案:A针对练习1关于导体和绝缘体,下列说法正确的是()A.通常情况下,液体都是导体B.非金属物质一定是绝缘体C.绝缘体在一定条件下可以变成导体D.导体导电都是靠电子针对练习2下列微粒中绕着原子核高速旋转的是()A.电子B.原子核C.质子D.中子2、A解析:原子是有原子核和核外电子组成;原子核带正电,电子带负电,电子绕着原子核高速旋转;原子核又是由质子和中子组成。

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[作图题知识点]
光学部分:光的直线传播光的反射平面镜成像光的折射透镜的三条特殊光线凸透镜成像
力学部分:受力分析杠杆示意图滑轮组的组装
电学部分:电路图和实物图电路设计家庭电路作图电磁作图
[简答题知识点]
声学部分:声音的产生和传播声音的特性噪声的危害和控制声的利用
光学部分:光的直线传播光的反射平面镜成像光的折射光的色散
力学部分:力的作用效果力的作用是相互的二力平衡摩擦力压
强浮力
功率机械能及其转化杠杆和滑轮
热学部分:温度计六种物态变化分子动理论内能的改变比热容热机
电学部分:摩擦起电电路的连接家庭电路
[作图题命题规律]
从近三年的中考题来看:(1)光学方面,以给出具体的情景进行作图为主,有光的反射、平面镜成像、光的折射等;透镜方面,有透镜的三条特殊光线作图;也有考凸透镜的三条特殊光线的成像作图等;(2)力学方面,考得较多的就是受力分析作图,即给出具体的情景,分析物体的受力情况。

另外,杠杆的示意图,滑轮组的组装也是考查的热点;(3)电学方面,主要考查四个方面,一是电路和电路图,即根据电路图连接实物或根据实物图画出电路图,有时单独出题,更多时候是混在实验探究题中;二是电路设计,即给出特定的情景,设计电路图,这是难点;三是家庭电路作图,这个一般不难,但要把握相关要点;四是电磁作图,主要考查磁感线、安培定则、电磁继电器等。

[简答题命题规律]
从近三年的中考题来看:简答题的考查一般占比较少,但也有考到,出题规律一般是结合当前的社会热点问题或生活中的常见现象结合物理知识命题。

[作图题中考策略]
光学作图:(1)光现象作图:综合平面镜成像的特点、光的反射定律,画出入射光线、反射光
拉力、牵引力、浮力、升力、磁力等。

一些常见力的方向:重力的方向竖直向下,摩擦力的方向与物体发生相对运动或运动趋势的方向相反,压力、支持力的方向与接触面垂直,浮力的方向竖直向上。

(2)杠杆示意图:要体现出杠杆的五要素,即支点、动力、阻力、动力臂和阻力臂。

要注意的是,力臂和力之间是垂直的关系。

(3)滑轮组的设计与绕线:绕线时要遵循“奇动偶定”的原则。

电学作图:(1)实物图与电路图:根据电路图连接实物时,通常要连接的是电流表、电压表、滑动变阻器,连接电表要先考虑量程,电流遵循“正进负出”的原则,连线不要交叉,电流表要串联在电路中,电压表要并联在电路中,连接滑动变阻器要“一上一下”,不能“同上同下”,而且串联在被控制的电路中。

(2)电路设计(包括电学黑箱):设计电路时,首先要注意用电器与用电器间的连接关系,其次要注意用电器与开关的关系。

①一个用电器的断开与闭合,会影响另一个用电器的通断,则这两个用电器之间是串联连接的,否则这两个用电器之间是并联连接的。

②开关闭合,用电器工作,开关断开,用电器不工作,则开关与用电器之间一定是串联连接的,不过这个时候,开关可能串联在用电器所在的支路上,也可能在干路上;开关闭合用电器不工作,开关断开用电器工作,则说明开关与用电器是并联连接的。

(3)家庭电路的连接:插座的连接是“左零右火”,三孔插座的上孔与地线相连;开关一端连灯泡、另一端连接在火线上;若灯是螺丝口灯泡,与螺丝套相连的接线柱应与零线相连接;保险丝要接在干路的火线上。

(4)电磁学作图,需要重点注意的是电磁继电器作图,控制电路一般是依次串联,工作电路的各用电器之间一般是并联的,具体的接线方法:电源的一端接动触点,两个静触点分别与之对应的用电器连接,然后回到电源的负极。

[简答题中考策略]
因为物理与生活密切联系,所以声、光、热、力、电各板块都可能涉及到简答题,但也有规律可寻,一般都是结合当前的热点问题,或是联系生活实际问题,所以要在平时密切留意生活中的物理现象,思考物理现象中的知识点。

简答题一般着重考查学生分析问题、合理选择信息和应用物理知识解决实际问题的能力,解答时要使用物理语言做针对性的回答,语言要精练,观点要明确,条理要清楚,内容要完整。

1.(2013•锦州)如图所示,发光点S 发出的某光线经平面镜发射后,发射光线恰好经过A 点,请在图中画出这条光线。

2.
(2012湖北恩施州)如图所示,光沿CO 射向半圆形玻璃砖的圆心O ,请在图中作出光线分别透过平直界面AOB 和圆弧形界面AMB 时的光路图。

3.(2011四川铜仁)下图A 给出物体AB 及像A ′B ′的位置,请在图中画出凸透镜及其焦点F 的大致位置。

4.(2013•锦州)如图所示,一个氢气球用绳子系在地面上,在风的作用下静止在空中时的场景,请作出氢气球所受力的示意图。

5.(2013雅安)如图所示, 课桌的重心在O 点, 若在课桌的C 点用力F 把桌腿
B 抬离地面, 在抬起时另一桌腿A没有滑动, 请在图中画出F 相对于A点的力臂l
1
和重力G的示意图。

6.根据实物图画出对应的电路图。

7.设计电路。

小雨同学想利用电源、灯泡L
1和L
2
、开关S
1
和单刀双掷开关S
2

滑动变阻器R,设计如下电路:S
1为总开关.当S
1
闭合时,若S
2
接在a处,两盏
灯都亮;若S
2接在b处,只有L
2
亮,且亮度可以调节。

请你根据他的想法帮他
设计电路。

8.(2013•锦州)生活在青藏高原的藏族同胞,主要采用烧、烤、炒的烹调方式做像糌粑(把干面粉炒熟)的一类食品,很少用平原地区居民常用的煮、炖一类
的烹调方式.请你用所学的物理知识分析:
⑴藏族同胞很少用平原地区地区居民常用的煮、炖一类的烹调方式的原因?
⑵为满足青藏高原的藏族同胞需要,若制造适合在青藏高原地区使用的
高压锅,应适当增大还是减小安全阀的质量?
1.(2012湖北黄冈)如图所示,暗室内有一盛水的水槽,水槽上方一激光束入射到平面镜(图
4.(2012•襄阳)在自动化生产线上,常用传送带传送工件,如图所示,一个工件与传送带一起沿水平向右做加速运动,不计空气阻力,请在图中画出工件受到的所有力的示意图。

5.如图所示,某人站在A处用一根绳子和两个滑轮提起物体B,画出最省力的绕线。

8.综合作图——小雨房间的灯:小雨的房间里有两盏灯,总开关S
1
闭合后,若
将单刀双掷开关S
2拨至a处,房间吸顶灯L
1
亮;若将S
2
拨至b处,壁灯L
2
亮,
并且可以通过开关S
3、S
4
控制,使它有三个不同的亮度。

现有一个电源、一个单刀双掷开关、3个开关、2个灯泡、2个相同的定值电阻和若干导线,请你设计上述电路,并将电路图画出来。

9.(2013年乐山)如图是利用太阳能给LED路灯供电的自动控制电路的原理示意图。

其中,R是光敏电阻,光敏电阻的阻值R随光照度的增强而减小。

白天,通过太阳能电池板与蓄电池回路将太阳能转化为化学能储存在大容量蓄电池内。

傍晚,当光照度小于一定值时,通过蓄电池与LED回路,路灯开始工作。

请用笔画线将电路原理图连接完整,使工作电路能正常工作(与触点的接线只能接在静触。

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