压强 专题训练 习题

压强 专题训练 习题 压强专题训练 基础巩固 1(根据《中华人民共和国道路交通安全法》规定，驾驶员必须使用安全带，如图7-7所示，其目的是防止汽车在紧急刹车时，由于 向前倾而造成伤害;其中安全带做得扁而宽大是为了减小安全带对驾驶员的 。 图7-8 图7-7 2.狮子、鳄鱼的犬牙(图7-8)像锥子一样尖锐、门牙像刀刃一般锋利，它们在猎食过程中起 作用。学生身边有很多类似的事例，请再举出一例 。 3(如图7-9所示，制造电工用的钢丝钳的材料是钢铁和橡胶，这主要利用钢铁的__________和橡胶的__________;钢丝钳的钳口很薄，是为了__________. 图9 图7-9 图7-11 7-10 4(太阳能飞机的表面遍布太阳能电池，该电池能将太阳能转化为,,,,,能供电动机转动(太阳能飞机机翼的横截面形状应如局部放大图,,,,,如图7-10所示(甲,乙)。 5.小明观察家中的坐便器(如图7-11所示)发现:冲洗前和冲洗结束后，B中水面位于水位l;冲洗时，水从A徐徐流入B后经C进入下水道，其间曾出现B中水面低于水位1、接近水位2的现象。上述现象可以用物理上的_______________知识来解释。 326(一头质量为6X10kg的大象，每只脚掌的面积为600cm，它的重力为 N，它四脚着地时对地面的压强为 Pa。若大象抬起一条腿，如图7-12所示， 它对地面的压强 (选填“变大”、“变小”或“不变”)。(g取10N, kg) (现有一架总质量为m的喷气式飞机，已知该飞机飞行时所受空72气阻力的大小与速度平方成正比，即f=kv(式中k为已知量).若飞机飞 图7-12 行过程中的耗油量可忽略不计. (1)该飞机在空中沿水平方向飞行时，飞机所受向上的升力是由机翼 上、下表面气流速度不同所产生的.若以机翼为参照物，则机翼上表面附近气流的速度________机翼下表面附近气流的速度. (2)在该飞机沿水平直线匀速飞行时，它上、下表面所受到的压力差为_________. (3)若该飞机以速度v沿水平方向匀速直线飞行的时间为t，则它在 这段时间内克服空气阻力所做的功W为___________. 8(生活中处处有物理:(1)生活在西部高原的人们烹饪食物往往是采 investigators carefully to verify that such credit party authenticity, when necessary, to the borrower unit verification and should strictly distinguish between regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to verify investigators should require borrowers to provide proof of use data and verified to ensure that lending purposes should be consistent with the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified uses. Personal loans should be a sharp distinction between consumer and business uses, management personal loans should refer to working capital loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guard against borrowers will loan money to the stock market, real estate, loan-sharking, private fund raising and other high risk areas or used for illegal business strictly preventing borrowers loans capital private public or misappropriated ... Understand borrowers ' credit business credit situation of the parties. Strict precautions against 图7-13 用炒、烤等方式制作，较少用煮的方式，这是由于高原地区的大气压较 ，水的沸点较 的缘故;(2)如图7-13所示，治病输液时，药水瓶口A处常插着两根塑料管B、C，其中插C管的目的是利用 使输液能顺利地进行( ,(一艘排水量为1 000t的货轮在海上航行，满载时受到的浮力是 N;它由海上驶入长江后，船体浸入水中的体积 (选填“变大”、“变小”或“不变”);货轮从上海驶往重庆要经过葛洲坝和三峡大坝船闸，船闸是根据 原理建造的。(取g=1N/Kg) 水坝的下部总要修得比上部宽，这是因为液体的压强随深度的增加而________;,,. 若水坝蓄水深度是20m，则坝底受到水的压强是_________Pa。 11.堵住打气筒的出口，打气筒的活塞越向下压越费力。此现象表明:在温度不变的条件下，一定质量气体的体积 ，气体的压强 。 5 12.封冰的江河，冰面所能承受的最大压强是2×10 Pa。某坦克质量为60t，两条履带着 2地面积共为5m，该坦克在冰面上行驶时对冰面的压强是__________ Pa，它最多还能装载质量_________t的人员和其它装备。(g取10N/kg) 13(请将下列物理器件在生活、生产中应用的实例各举一例: ?连通器_____________;?杠杆_______________。 14.如图7-14所示，c为扎在口管下端的小气球，从口管向内吹气可以使小气球c膨胀(从b管向瓶外抽气，能达到同样效果，其原因是 ( 15(2005年5月22日，中国登山测量队队员又一次成功登顶，对珠穆朗玛峰重新进行了测量。测量队员向上攀登的过程中，受到的大气压强逐渐 ;队员要使用高压锅把饭煮熟，是为了 。另外，测量队员需要携带氧气瓶，其作用是 ;队员登山时常携带能自动加热的方便食品来补充能量，加热的原理是利用生石灰跟水反应放出热量，反应的 图7-14 化学方程式为 。 16(根据以下示例，写出以下四点在各方面应用中的相关事例(每种各举一例) 示例:红外线:电视机遥控器利用红外线进行遥控 (1) 太阳光:_____________________________________________________________; (2) 超声波:_____________________________________________________________; (3) 凸透镜:_____________________________________________________________; (4) 大气压强:___________________________________________________________( 17.科学知识告诉我们:气体的流速越快，压强越小。 为了探究液体压强和流速的关系，做了如下实验:根据图7-15示， 你得出的结论是:_______________________________。下列四种情 形中，哪种情形能够 运用上述的实验规律进行解释( )。A、乒乓球运动员拉出的弧圈B A 图7-15 球能急速旋转而下沉 B、将氢气球放手后，它会漂向空中 C、直升飞机能够停在空中一定高度处 D、船舶航行时应避免两艘靠近的船并排前进 18.唐代诗人杜甫在《茅屋为秋风所破歌》这首诗中写道:“八月秋高风怒号，卷我屋上三重茅”。以上诗句中包含的物理知识有:(只写两条) (1) 。 (2) 。 2rowers ' credit business credit situation of the parties. Strict precautions againstor used for illegal business strictly preventing borrowers loans capital private public or misappropriated ... Understand bor sharking, private fund raising and other high risk areas-d against borrowers will loan money to the stock market, real estate, loanrking capital loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guarto wo uses. Personal loans should be a sharp distinction between consumer and business uses, management personal loans should referonsistent with the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified d be cverify investigators should require borrowers to provide proof of use data and verified to ensure that lending purposes shoulish between regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to should strictly distinguinvestigators carefully to verify that such credit party authenticity, when necessary, to the borrower unit verification and 19(如图7-16所示的四种现象中，属于减小压强的是( ) 图7-10 49.图7-22中，采用减小受力面积的方法增大压强的事列是 ( )32.A 图7-16 20(下列事例中，哪个 措施 《全国民用建筑工程设计技术措施》规划•建筑•景观全国民用建筑工程设计技术措施》规划•建筑•景观软件质量保证措施下载工地伤害及预防措施下载关于贯彻落实的具体措施 的目的是为了减小压强( ) A.注射器的针头很尖 B(为了易于把吸管插入软包装饮料盒内，吸管一端被削得很尖 C(火车铁轨不直接铺在路面上，而铺在一根根路枕上 D(菜刀用过一段时间后，要磨一磨 21.游客潜入海底观光，在水面下不断下潜的过程中，受到的浮力和压强的变化情况是( ) A.浮力逐渐变大 B.浮力逐渐变小 C.压强逐渐变 D压强逐渐变小 22(很多动物为了适应自身生存的环境，进化出了符合一定物理规律的身体部位，如图7-17 所示的四种动物器官中，具有增大压强功能的是( ) 图7-17 23.如图7-18所示，水平桌面上有甲、乙两个质量和底面积 都相等的容器。向容器中注入高度相等的水，水对容器底部 的压强分别为P、P，装水后的容器对桌面的压力分别为甲乙 F、F。则( ) 甲乙 A.P=P，F=F B.P,P，F=F 甲乙甲乙甲乙甲乙 图7-18 C.P=P，F,F D.P,P，F,F31.C 甲乙甲乙甲乙甲乙 24(.向竖直放置的下端扎有橡皮膜的玻璃管内倒人一些水， 橡皮膜就会向外凸出;使玻璃管从竖直位置逐渐倾斜，橡皮膜凸出的程度将 ( ) A(逐渐变，J B(逐渐变大 C(保持不变 D(无法判断 25.下列事例中不是利用大气压的是【 】 3business credit situation of the parties. Strict precautions against ital private public or misappropriated ... Understand borrowers ' creditsharking, private fund raising and other high risk areas or used for illegal business strictly preventing borrowers loans cap-ers will loan money to the stock market, real estate, loanborrowtal loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guard against oans should be a sharp distinction between consumer and business uses, management personal loans should refer to working capional lwith the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified uses. Perstors should require borrowers to provide proof of use data and verified to ensure that lending purposes should be consistent estigan regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to verify invthat such credit party authenticity, when necessary, to the borrower unit verification and should strictly distinguish betweeinvestigators carefully to verify A.把吸盘式挂衣钩紧贴到墙上后可挂衣服 B.用胶头滴管吸取药液 C.茶壶的盖上留一小孔，水才容易倒出 D.用力压打气筒的活塞，把气充进轮胎中 26(取一个小瓶，用嘴从瓶内吸出一部分空气，小瓶就会挂在嘴唇上，这是因为( ) A(嘴把瓶子吸住了 B(瓶外气压大于瓶内气体的压强 C(瓶内气体压强的作用 D(嘴和瓶之间的摩擦作用 27(关于大气压强现象，下列说法中正确的是 [ ] A(托里拆利实验表明，大气压的值是固定不变的 B(1.01×105帕大气压能支持15米高的水柱 C(在同一地点，同时用粗细不同的玻璃管做托里拆利实验，测得的大气压的值相同 D(人体不会被大气压力压扁，是因为人体内的气体压强大于空气的压强 2,.坦克要越过壕沟时，可将备有的气袋放入壕沟，给气袋充满气，这样坦克通过气袋就像走平地一样。当坦克的前一半履带压在气袋上时，对气袋的压力和压强分别为F和P。设11坦克在水平地面上行驶时，对地面的压力和压强分别为F和P，坦克前后是对称的。则以22 下有关两种情况下压力、压强的比较结果，正确的是 ( ) A(F=F P=P B(F=1/2F P=P 12 1212 12 C(F=1/2F P=1/2P D(F=F P=2P 12 1212 12 29.如图7-19所示，把一只玻璃杯的杯口朝下，竖直按入水中，在杯子按入水中的过程中则 ( ) A.杯内充满水 7-19 B.水不能进入杯内 C.水进入杯中，杯中空气压强越来越小 D.水进入杯中，杯中空气压强越来越大 230.质量为1kg的平底空水桶，底面积为700cm。水桶内装有30cm深的水，放在水平地面上，如图甲所示，水对水桶底的压强比水桶对地面的压强小1000Pa。当小明用竖直向上的力F提水桶，但没有提起来时，如图7-20乙所示，水桶对地面的压强为1800Pa。则下列7-20 选项正确的是(g取10N/ kg) A(水桶内水的质量为28kg B(水桶内水的质量为27kg C(F的大小为154N D(F的大小为126N 31 (在五一游艺晚会上，陈思同学演示了如图7-21示 的实验，排在一条线上的三个碗，中间碗内放一个乒乓 球，当用小管向球斜上方吹气，乒乓球将( ) A、仍静止 B (运动到左碗 7-21 C、运动到右碗 D (无法确定 32、如图7-22所示，甲、乙两个实心圆柱体放在水平地 面上，它们对地面的压强相等，则下列判断正确的是 ( ) A(甲的密度大，甲受的重力小 B(甲的密度小，甲受的重力小 C(甲的密度小，甲受的重力大 7-22 D(甲的密度大，甲受的重力大 4rowers ' credit business credit situation of the parties. Strict precautions againstor used for illegal business strictly preventing borrowers loans capital private public or misappropriated ... Understand bor sharking, private fund raising and other high risk areas-d against borrowers will loan money to the stock market, real estate, loanrking capital loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guarto wo uses. Personal loans should be a sharp distinction between consumer and business uses, management personal loans should referonsistent with the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified d be cverify investigators should require borrowers to provide proof of use data and verified to ensure that lending purposes shoulish between regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to should strictly distinguinvestigators carefully to verify that such credit party authenticity, when necessary, to the borrower unit verification and 33.完全相同的8块橡皮，每块橡皮的长、宽、高为4:2:1。小明同学在水平桌面上把它们摆放成了如图7-23所示的四种形式，其中对桌面压强相等的是( ) A.甲与乙 B.甲与丁 C.乙与丙 D.丙与丁 图7-23 34(小亮同学从超市买来一个玻璃瓶装的铁皮盖罐头(想把瓶盖打开，可是怎么也拧不动(小亮的哥哥用螺丝刀沿瓶盖的边轻轻撬了几下，一拧就打开了，这主要是因为用螺丝刀撬瓶盖可以( ) A(增大瓶盖直径，减小瓶盖侧壁对瓶的压力 B(减小瓶盖与瓶口的接触面积 C(减小瓶内外气体的压力差 D(由于撬了盖的一边(而增大了盖的另一边的压力 35.为了保护塑胶跑道一些学校禁止在跑道上使用带长钉子的运动鞋。这是因为运动员穿上该种钉鞋后对跑进的压力几乎不变.但跑道的( ) ,.受力面积减小，压强减小,,受力面积增大，压强增大 ,(受力面积减小，压强增大D.受力面积增大，压强减小 36(图7-24下列现象中能说明气体的压强跟流速有关的是( ) 7-24 37(青藏铁路已全线贯通，即将投入运营的高原列车有完善的供氧系统和完备的医疗应急系统，这样做是因为( ) A(高原空气稀薄，大气压强小 B(高原空气稀薄，大气压强大 C(高原空气稠密，大气压强小 D(高原空气稠密，大气压强大 38.秋竹同学在厨房帮妈妈做饭时观察到了一些现象，并用所学物理知识进行了解释，其中解释不正确的是 ( ) ((( A.磨刀，是为了增大压强 B.高压锅做饭熟的快，是因为压强增大，沸点升高 C.打开电冰箱时冒出的“白烟”，是冰箱内蔬菜水果等蒸发产生的水蒸气 D.电饭锅用三脚插头和三孔插座，是为了防止锅体漏电造成触电事故 39.如图7-25所示，放在水平桌面上的A、B两圆柱形容器中，装有质量相同的不同液体，并且液面相平，比较A、B两容器底部所受液体产生的压力和压强( ) F,FP,PA(， ABAB F,FP,PB(， ABAB F,FP,PC(， ABAB 5business credit situation of the parties. Strict precautions against ital private public or misappropriated ... Understand borrowers ' creditsharking, private fund raising and other high risk areas or used for illegal business strictly preventing borrowers loans cap-ers will loan money to the stock market, real estate, loanborrowtal loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guard against oans should be a sharp distinction between consumer and business uses, management personal loans should refer to working capional lwith the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified uses. Perstors should require borrowers to provide proof of use data and verified to ensure that lending purposes should be consistent estigan regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to verify invthat such credit party authenticity, when necessary, to the borrower unit verification and should strictly distinguish betweeinvestigators carefully to verify 图7-25 D(， F,FP,PABAB 40(图7-26是家用煤气灶灶头的示意图使用时打开煤气阀门，拧动点火装置，煤气和空气在进口处混合流向燃烧头被点燃，而煤气不会从进口处向空气中泄漏，其原因是( ) A.进口处煤气流速小，压强大于大气压强 B.进口处煤气流速小，压强小于大气压强 C.进口处煤气流速大，压强大于大气压强 D.进口处煤气流速大，压强小于大气压强 图7-26 能力提高 41(某同学用三块相同的海绵和三个相同的小桌、砝码做实验，从中探索压强跟压力，受力面积的关系，如图7-27所示，其中说明压强跟受力面积有关的两次实验是( ) A(甲和乙 B(甲和丙 C(乙和丙 D(任意两个都可以 图7-27 42.小明和小华在学习了液体压强的知识后用加长的饮料瓶 做了如图7-28所示的实验，在饮料瓶中灌满水，然后在瓶的 a、b处各扎一个小孔，观察其后发生的现象( ?他们发现从小孔b中射出水流的速度比小孔a中的大， 你认为其原因是___________________________________( ?经过反复的试验，他们发现从小孔中射出水流的射程s (从小孔处到落地点的水平距离OA)跟小孔在水中的深度h和 小孔到地面的高度H这两个因素有关(为了研究水流的射 程s与h、H之间的关系，他们将饮料瓶放置在水平桌面边缘，图7-28 看到如图所示的现象，由此他们得出了结论:小孔距水面的深 度h越大，水流的射程s越大( 你认为根据图示的现象能否得出上述结论?请说明你的理由( ?测量水流的射程s，需用__________ (填测量工具)(请你运用学过的物理知识帮助他们确定水流射程起点O的位置，写出具体的方法。 ?他们在实验中测得的数据如下表所示: 实验序号 小孔高度H,m 小孔深度h,m 小孔深度的平方水流射程s,m 1/2根 ,m 1 0(64 0(16 0(40 0(64 2 0(64 0(36 0(60 0(96 3 0(64 0(64 0(80 1(28 6rowers ' credit business credit situation of the parties. Strict precautions againstor used for illegal business strictly preventing borrowers loans capital private public or misappropriated ... Understand bor sharking, private fund raising and other high risk areas-d against borrowers will loan money to the stock market, real estate, loanrking capital loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guarto wo uses. Personal loans should be a sharp distinction between consumer and business uses, management personal loans should referonsistent with the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified d be cverify investigators should require borrowers to provide proof of use data and verified to ensure that lending purposes shoulish between regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to should strictly distinguinvestigators carefully to verify that such credit party authenticity, when necessary, to the borrower unit verification and 4 1(0 0(16 0(40 0(80 5 1(0 0(36 0(60 1(20 6 1(0 0(64 0(80 1(60 根据表中数据，可以得出结论:当小孔高度H一定时，水流射程s与_________成正比( 43(科学兴趣小组的吴丽同学看到别人用烫开水把一个凹瘪的乒乓球“吹”圆，受此启发，她与兴趣小组的同学猜测:盛有空气的密闭容器(体积不变)中的气体压强与它的温度有关系，其中小组成员张敏认为容器内的气体压强与它的摄氏温度成正比，而吴丽同学认为与摄氏温度的平方成正比。他们为了验证这些猜想是否正确，设计如下实验; 图7-29 在实验室张老师的指导下，取一牢固的密闭性好又能加热的钢制气罐，通过盖上的特殊孔，在气罐内按置了温度、气压传感器，并与对应的显示仪连接，见图7-29。对气罐 缓慢加热，并记录了如下表的数据: (1)请在答题卷的对应坐标上作出此气罐的气压与温度的关系图象。 (2)根据数据和图象，得出本实验中的气压(p)与气温(t)关系的数学表达式为p= 帕，由此可判定 同学的猜测是不正确的。 44.实验桌上有两只大烧杯，其中一杯盛有纯净水，另一杯 盛有盐水。老师告诉小敏盐水的密度大于纯净水的密度，希 business credit situation of the parties. Strict precautions against ital private public or misappropriated ... Understand borrowers ' creditsharking, private fund raising and other high risk areas or used for illegal business strictly preventing borrowers loans cap-ers will loan money to the stock market, real estate, loanborrowtal loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guard against oans should be a sharp distinction between consumer and business uses, management personal loans should refer to working capional lwith the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified uses. Perstors should require borrowers to provide proof of use data and verified to ensure that lending purposes should be consistent estigan regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to verify invthat such credit party authenticity, when necessary, to the borrower unit verification and should strictly distinguish betweeinvestigators carefully to verify 7 图7-30 望她用压强计将它们区别开。如图7-30所示，小敏将压强计的金属盒(探头)先后浸没到甲、乙两杯液体中，分别记下压强计U形管两侧的液柱高度差h和h。她发现h小于h，于甲乙甲乙是认为乙杯子中盛的是盐水。老师指出小敏的实验过程是不正确的。小敏认真思考后发现自己在实验过程中没有控制变量，并提出了新的实验思路如下:将压强计的金属盒(探头)先后浸没到甲、乙两杯液体中，压强计U形管两侧的液柱高度差分别用hˊ和hˊ表示，使h甲乙 与hˊ ， 甲乙ˊ ， 比较 则 的一定是盐水。请你将小敏的实验思路补充完整。(北京市) 545.学习了大气压的知识以后，小明对大气压强通常有1.0×10Pa这么大存有疑问，想亲自证实一下( (1)小明买来一个塑料挂钩，把它的吸盘贴在玻璃餐桌的下表 面，如图7-31所示，测出塑料吸盘与玻璃的接触面积为lOcm;又 找来一个轻塑料桶(质量可忽略不计)，在桶中装8L水;经过计算， 图7-31 他认为把塑料桶挂到挂钩上不会把吸盘拉掉(请你写出计算过程 和判断依据((g取10N,kg) (2)当小明把水桶挂到挂钩上时，吸盘却被拉掉了，是大气压没有那么大还是其他原因?请发表你的看法( 46(汽车如图7-32是我们熟悉的交通工具，它给我们的生活提供了便 利,促进了社会经济的发展。汽车应用了许多物理知识。请你运用所学的 物理知识解答下列问题: ?汽油机是汽车的“心脏”。汽油机工作时 冲程将内 能转化为机械能。 ?)载重汽车都安装了较多的车轮，且轮胎上有凸凹不平的花纹， 其目的 7-32 是 ; ?据报道因车辆超载损坏公路，每年给我国造成的经济损失高达300亿元。国家规定， 54载重车辆的轮胎，对地面的压强应控制在7×10Pa以内。有一辆重2×10N的6轮汽车，2如果每个车轮与路面的接触面积为200cm，请你计算该汽车允许装载的货物的最大质量是多少,(g取10N,kg) (4)虽然汽车在现代社会中有很多重要作用，但也造成了一些不利的影响，如能源消耗、大气污染、噪声污染、交通事故等等。请你结合物理知识，就如何减小汽车的某项不利影响，提出一条合理化建议: 。 8rowers ' credit business credit situation of the parties. Strict precautions againstor used for illegal business strictly preventing borrowers loans capital private public or misappropriated ... Understand bor sharking, private fund raising and other high risk areas-d against borrowers will loan money to the stock market, real estate, loanrking capital loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guarto wo uses. Personal loans should be a sharp distinction between consumer and business uses, management personal loans should referonsistent with the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified d be cverify investigators should require borrowers to provide proof of use data and verified to ensure that lending purposes shoulish between regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to should strictly distinguinvestigators carefully to verify that such credit party authenticity, when necessary, to the borrower unit verification and 47(冬天的一个星期天,小伟和同学们在公园的湖边玩耍,他发现人可以在封冻的冰面上行 2走，若人的每只鞋底面积是125cm，体重为500N的人恰好可以通过，而小伟的每只鞋底面 2积是175cm，体重为500N,则他不仅可以从冰上通过,他最多还可以负重多少通过冰面呢, 48.通常情况下，物体压在同样的泥地上，如果压强相同则压痕深度相同(野生动 物调查员在野外泥地上发现黑熊刚留下的足印(为了估算黑熊的质量，他把一个底面积是 210cm的容器放在足印附近的泥地上，再慢慢往容器中倒入沙子，直到容器在泥地上留下与 黑熊足印深度相同的痕迹，测出此时装了沙的容器总质量为1.25 kg((g取10N,kg) 4 (l)装了沙的容器对泥地的压强多大,P=1.25×10×/(10×0.00001)=1.25×10Pa 2 (2)量出黑熊与地接触的足印痕总面积共800cm，估算黑熊的质量有多大, m=(800/10) ×1.25=100kg 49(据报道，某市图书馆 白天停水，由于管理人员 的疏忽，水龙头处于打开 状态，排水口被塞子堵住， 夜里水通了，水池里的水 很快溢出，漫延至图书馆 各处，造成很大的损失(小7-33 明同学是学校图书馆的义 务管理员，看了这则报道 后，动手自制“自动拔塞器”(该装置能够在类似情况下，自动拨开塞子排水(小明首先在水池某处做记号，作为警戒线;然后将塞子堵住排水口，打开水龙头放水至警戒线，用弹簧测力计向上拉塞子，当弹簧测力计的示数为5N时，塞子被拔出;接着把水池中的水放掉，选择合适的空心密闭塑料瓶，调节塑料瓶与塞子间绳子的长度，向水池中重新放水，使得当水涨至警戒线时，塑料瓶就能把塞子拔出，如图7-33所示(已知塑料瓶的质量为30g，总体积为750mL，g取10N,kg，问塑料瓶排开水的体积为多大时就能将塞子拔出, 50小明用一满瓶纯净水和放在水平桌面上的海绵做实 验，研究“影响压力作用效果的因素”，如图7-34所示(做 着做着小明想，一瓶纯净水能产生多大的压强，竟把海 绵压陷得那么明显(于是就开始想办法计算它(他从商 标纸上查到这瓶水的“净含量”是600mL 3(1ml,l?);掂了掂同样的空瓶确实很轻，重力可忽图7-34 22略不计;又测出瓶底面积为35cm，瓶盖面积为7cm(根 据小明收集的数据，请你计算 ?这瓶纯净水净重多少,(取g,10N,kg) ?瓶子正放时对海绵的压强是多少, 9business credit situation of the parties. Strict precautions against ital private public or misappropriated ... Understand borrowers ' creditsharking, private fund raising and other high risk areas or used for illegal business strictly preventing borrowers loans cap-ers will loan money to the stock market, real estate, loanborrowtal loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guard against oans should be a sharp distinction between consumer and business uses, management personal loans should refer to working capional lwith the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified uses. Perstors should require borrowers to provide proof of use data and verified to ensure that lending purposes should be consistent estigan regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to verify invthat such credit party authenticity, when necessary, to the borrower unit verification and should strictly distinguish betweeinvestigators carefully to verify ?要使瓶子倒放时对海绵的压强与正放时相同，简单的方法是什么, 51. 黄华路小巷里的纪念碑“血泪洒黄华”(图7-35)，铭记着日本侵略中国的一段历史，承载着日本欠下中国人的一份血债。碑身高约1.5m，宽约0.6m、厚约0.1m(已知碑 33石密度为2.6×10kg,m，求:(本题g取10N,kg) (1)纪念碑的碑重, (2)它对地面的压强, 中考冲刺答案 图7-35 1.惯性，压强 2.减小受力面积增大压强 斧头,针头等 3(硬度大 绝缘性能好 增大压强 4(电 乙 5.液体压强(或连 45通器) 6. 6×10 2.5×10 变大 7. (1).大于 (2)mg, (3) 3kvt 8. 低(或小)低 大气压) 9. 10. 11. 5 12.1.2×10，40 13(?水壶与壶嘴组成连通器(其它如:锅炉水位计、水塔与自 来水管组成连通器、船闸等均可) ?瓶盖起子(其它如:剪刀、镊子、钢丝钳等符合题意即可) 14(抽气使瓶子内压强变小，气体就从口管进入气球c使其膨胀 15.减小 增大锅内气体压强，升高液体沸点 供给呼吸 CaO+H0=Ca(OH)2 2 16.1)太阳灶用太阳光加热物体;或湿衣服用太阳光加快蒸发(合理就给分) 2)声纳利用超声波回声定位;或医疗器械用超声波检查身体内脏器官(击碎结石)等 3)远视者利用凸透镜能看清报纸上清晰的字;或照相机利用凸透镜作镜头照相等 4)吸盘式挂衣钩利用大气压强压紧在墙上;或利用大气压强，人可以用吸管吸汽水等。 17(液体流速越快，压强越小 D 18.(1)风怒号是空气振动产生的声音 (2)力可以改变物体的运动转状态 19(C 20.C 21.C 22 .B 23.C 24.A 25. D 26.B 27.C 28.B 29.D 30.BC 31.C 32.A 33.BC 34(C 35(C 36(A 37(A 38.C 39.D 40.D 能力提高 41.B 10rowers ' credit business credit situation of the parties. Strict precautions againstor used for illegal business strictly preventing borrowers loans capital private public or misappropriated ... Understand bor sharking, private fund raising and other high risk areas-d against borrowers will loan money to the stock market, real estate, loanrking capital loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guarto wo uses. Personal loans should be a sharp distinction between consumer and business uses, management personal loans should referonsistent with the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified d be cverify investigators should require borrowers to provide proof of use data and verified to ensure that lending purposes shoulish between regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to should strictly distinguinvestigators carefully to verify that such credit party authenticity, when necessary, to the borrower unit verification and 42 543((1)略 (2)P=[1.04+0.004×(t,10)]×10 张敏 44(相等 两侧的液柱高度差 高度差大 2-345.?吸盘面积:S=10?=10? 5-3吸盘受到的大气压力:F=PS=1.0×10Pa×10?=100N 33-33水的质量:m=Ρv=1×10kg/m×8×10m=8kg 水的重力:G=mg=8kg×10N/kg=80N 因为G,F，所以装水塑料桶挂到挂钩上不会把吸盘拉掉 ?不是大气压没有那么大，可能是吸盘内没有完全压成真空或吸盘与玻璃接触面粗糙，有漏 气现象 4346.(1)作功 (2)增大与地面的摩擦 (3)m=(PS-2×10N)/g=6.4×10kg=6.4(吨) (4)略 (200N 47448.(1) P=1.25×10×/(10×0.00001)=1.25×10Pa (2) m=(800/10) ×1.25=100kg 49(由T=F浮-G得F浮=T+G=5+0.03×10=5.3N 3由F浮=ρgV得V=F浮/ρg=5.3/(10×10)=5.3mL 排排 350((1)V=1.5m×0.6m×0.1m = 0.09 m 333m =ρV= 2.6×10 kg /m×0.09 m= 234 kg G = mg = 234kg×10N /kg = 2340N (2)(因石碑水平自由放置) 所以:F = G = 2340N 2S = 0.6m×0.1m = 0.06 m 2P = F / S = 2340N/ 0.06 m =39000Pa 11business credit situation of the parties. Strict precautions against ital private public or misappropriated ... Understand borrowers ' creditsharking, private fund raising and other high risk areas or used for illegal business strictly preventing borrowers loans cap-ers will loan money to the stock market, real estate, loanborrowtal loans required to verify authenticity, consumer loans should ensure a clear, true and reasonable. Strictly guard against oans should be a sharp distinction between consumer and business uses, management personal loans should refer to working capional lwith the relevant laws and regulations and national policies. Bank ban on issuing personal loans without specified uses. Perstors should require borrowers to provide proof of use data and verified to ensure that lending purposes should be consistent estigan regular employees, temporary employees, categories and on the job, retirement, early retirement, etc. Purpose to verify invthat such credit party authenticity, when necessary, to the borrower unit verification and should strictly distinguish betweeinvestigators carefully to verify