励才部分暑假作业答案.doc

数学参考答案：预习作业（1）圆自主学习： 见九上课本P106-P107尝试练习： 1、上，外，上 2、（1）内，（2）5，（3）外 3、圆内，圆上，圆外 4、圆上， 5、以点P为圆心，6cm为半径的圆 6、C巩固练习： 1、（1）B在圆上，C在圆外，D在圆外 （2）B在圆内，C在圆外，D在圆上 （3）B在圆内，C在圆上，D在圆内 2、提示：连接AC,找AC的中点O，连接OD,OB。说明OB=OA=OC=OD。 3、提示：连接EM,DM。说明EM=BM=CM=DM圆的有关概念自主学习：见九上课本P108-P109尝试练习：1、2、 3、4、 5、 6、 7、提示：说明COBDOA 8、提示：连接OA,OB,说明OACOBD巩固练习：1、A=28 2、BC=8 3、提示：连接OC，解得OC=5，AB=10 P110 5、B=55 6、提示：说明AODBOC 7、提示：说明OCD=OAB 8、提示：连接OD,则OD=AB=2，再说明四边形OFDE是矩形，从而EF=OD=2.预习作业（2）圆的对称性自主学习：见九上课本P111-P112尝试练习：1、90 2、60 3、60 4、60 5、相等，提示：说明AC=BC巩固练习：1、AC=BD,连接OC,OD说明：OCEODE 2、BE 的度数为1203、提示：连接AC,BD说明ACE与BDF为等腰三角形，从而得到AE=AC,BF=BD圆的对称性（2）学习内容：例1，例2 （1）OA=5 (2)3OP5达标检测：1. 2. 3.AM= 4.连接OP作垂直于op的弦 5.OP=3 6.R=5 7. 8. 1 9. 1或7 10.(1)AO=10 (2)2 11. 265.3圆周角（1）尝试练习(1)BDC=_35_,(2)BOC=_70_(3)如图，点A、B、C在O上， 若BAC=60，求BOC=_120_; 若AOB=90,求ACB=_45_ (4)例题：见课本达标检测 1、延长CD交圆于点E，方法与例4相同2、与BOC相等的是：BDC, BAC, ECA, OBA3、ABD=35 4、AOB=_80_，OAB=_50_5、ABD_30_6、与ABD相似的三角形有_CED,_ AEC圆周角2一、 同弧或等弧所对的圆周角都等于所对的圆心角的一半二、 直角三、 过四、 直径或半圆所对的圆周角等于90 90所对的弦是直径五、 略六、 50 100七、 提示：连接OC,OE AE=55、 例题1、 AD=2、 CEB=1003、 略4、 提示：连接AD证垂直平分线5、 提示：连接CD，AC=确定圆的条件八、 无数个九、 无数个 垂直平分线上十、 不能 结论：不在同一直线上的三点可以确定一圆十一、 三角形的三个顶点确定一个圆这个圆叫做三角形的外接圆 如果圆上有三个不重合的点，则这三点构成的三角形叫做圆的内接三角形外接圆的圆心叫做三角形的外心到三角形三个顶点距离相等 十二、 锐角三角形：外心在圆内 直角三角形：外心在圆上 钝角三角形：外心在圆外1. 尝试解决1. 内接 外接2. 一四错误，三正确3. r=5, S=254. 略2. 例题精讲例1.1.1002.1003.120或60例二.提示：连接OB,OC过O点作OD垂直于BC用垂径定理解 r=3 r=例三.连接AD并延长叫BC于D点，连接OB，OCr=例四.略3. 课堂检测1. 略2. 1)r=6.5 2)r= 3)AB=或英语参考答案：五一 完型填空A. 1-5 DBABD 6-10 CBBDB 11-15 ADCDCB. 1-5ACDAC 6-10 BACBA 11-15 CCDBD二 阅读理解1-5DABCD三 阅读表达1.all over 2.你可以使用英特网代替图书室3.An E-mail is a way to send messages.4.Its much quicker and cheaper than sending a letter.5.Quick easy and interesting - thats the Internet四 缺词填空 1-5 broken , throw, left, ready ,usually 6-10 seats, belongs mistakes voice successful五 书面表达Dear principal: I would like to recommend my classmates as the new leader of our school station.I think he will been excellent leader because he has many good qualities. He is always ready to help others. He often helps us us with our homework and explains things to us. At .school he helps other students .For example,he shows the Grade 7 students how to use the library. He is energetic and often does things for us. He is good at making or planning things. Last term, he hosted a charity and he has the ability to be the leader. He can get on well with his classmates. Everyone thinks he has the qualities to be a good leader of the radio station. We hope you agree with us. 六完形填空1620 ADBBD 2125 ADABD 2630 DBDAD阅读理解3135 CBDAB 3640 DCDAB 阅读表达1. share with 2. 过了一会儿，狮子向他们慢慢走来，然后越跑越快。3The man shouted in a loud voice and began to run away.4The girl asked us if we knew what the man had said5 People have different ways to express love.缺词填空1. understand 2.same 3. advantages 4. important 5. seems 6. after 7. provide 8. until 9. deal 10 contol 七、书面表达（满分20分）Dear Mum and Dad,Time flies! Ive been here for nearly a year. Im very pleased to find that our school is really a good one. The students in our school is really a good one. The students in our school work hard at their lessons. We take an active part in activities. We are friendly to each other and always ready to help each other.The teachers here all enjoy their work and they love their students. They work hard and do what they can do to help us. And the students respect their teachers. We get on well with each other. The students in our school try their best to keep the school yard clean and tidy. They never throw waste about or pick the flowers.In a word, I am deeply impressed by the harmonious atmosphere in this school. I love my new school.Yours,Frank七6、 ABACA DAABC 7、 DCADC BACBB ABDCB8、 1. Italy world 2. He passed away on September 6th, 2007.3. 无论我们选择什么，我们都应该全身心投入。4. It took 7 years of study and hard work before I made my first appearance on the stages.5. Pavarottis successful career shows that ., then well succeed surely.四、more everyone needs possible without do longer farms moving only6、 The Internet is playing a more and more important part in our daily life. On the net, we can learn news both at home and abroad and all kinds of other information as well. We can also send messages by e-mail, make phone calls, go to net school, read various kinds of books and learn foreign languages by ourselves. Besides, we can enjoy music, watch sports matches and play chess or cards. On the net, we can even do shopping, have a chat with others and make friends with them. In a word, the internet has made our life more colorful. But some teenagers love themselves into the Internet. They often spend much time playing computer games, even visit some unhealthy websites. Thats harmful to them.So we should learn to use the Internet properly.物理参考答案：第十四章欧姆定律（答案）第一节1A2D3D4C5A6A7B8C9D10C11甲、丙12阻碍、长度、横截面积、温度、无关13有关、变大、小 14减小、长度、横截面积1510、10 16绝缘体、横截面积、电阻17导体、弱 18串、灯泡的亮暗程度、电流19电压、电流、电阻；F、CG、S；研究液体蒸发快慢的因素等202、4；较大、电流太小或电阻太大；C第二节1A2长度、电流、电阻箱33608、099994A、C或D 50、6650表示最大阻值为50，1A表示允许通过的最大电流为1A、0、25、b7B8C9B10C11D12A13断开、A；灯泡断路；连图略14杠杆；滑动变阻器；电流；减小、减小、增大15D、C、A、B；47、47；等效替代法16滑动变阻器；略第三节1B2A3A4C5B612、1、12、0、1273：28电阻一定，电流与电压成正比；不成、不符；没有控制电压一定920；20、0.15A；2010492114512用一个24的电阻与灯泡串联1312V；1.2A；1.5A；8 1406A；3.6 1505A；816电压表的变化范围为：3V6V；电流表的变化范围为：0.3A0.6A第四节（一）自主学习2略；右；0.25、10；温度巩固练习11.5V、0.075A；80；60 240、10（二）自主学习16V2B31.2106Pa；4.2108J；14.2kg、200N、0.03A巩固练习1滑动变阻器、亮暗程度2D 3减小、增大；E1R1= E2R2 ； ；8综合实践活动自主学习1不能、应将滑动变阻器的滑片P移到阻值最大处；10、0.3A、滑动变阻器的允许通过的最大嫌小，换大的210；将灯泡和滑动变阻器串联；滑片P在移动的过程中，灯泡两端的电压会超过2.5V；14巩固练习1A2B3控制