九年级物理计算题训练

We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysiand system handover; to strengthening BFS++, and ER, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \o.\To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \nterprise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction 复习：

一．主要公式： 1. 速度的公式：v＝

S t2. 计算密度的大小： 利用公式ρ＝

V排mG（或者ρ＝；ρ＝ρ液） ?液G?FVV物3. 压强的计算：利用公式P=

F 液体压强公式：p =ρgh S液

4. 浮力的计算：利用公式F浮?G排＝ρ5. 功的计算，利用公式W＝FS 6. 功率的计算，利用公式P＝

g V排＝G物

WFS?Fv） P=Fv （=

tt7.机械效率的计算，利用公式：η＝8. 杠杆的平衡条件:F1L1=F2L2 9. 热值计算公式：Q=mq

W有用W总×100%

10.热量计算公式：Q吸=cm(t-t0) Q＝Cm△t

二．计算训练

1.太阳能热水器是一种常见的利用太阳能的装置。某品牌太阳能热水器，在晴天能接收到的太阳能平均辐射强度(用R表示)为R=300J／(m2·s)，它表示每平方米面积上一秒内接收到的太阳能为300J。该太阳能热水器集热管接收阳光照射时的有效面积是2m2，贮水箱中盛有0.1m3的水。求：(1)贮水箱中水的质量。(2)若在阳光下照射70min，所接收到的太阳能全部用来加热水，贮水箱中的水温可升高多少度。[ρ水=1．0×103kg／m3，C水=4．2×103J／(kg·℃)]

2.（天津市）炎热夏天，小丽将装有0.6kg水的塑料瓶放入电冰箱冷藏室，待水降温后饮用。水由35℃降至5℃过程中放出的热量为多少？［水的比热容c=4.2×103J/（kg·℃）］

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy! We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysiand system handover; to strengthening BFS++, and ER, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \o.\To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \nterprise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction 3. 将一正方体金属块挂在弹簧测力计上称量.当金属块在空气中时， 弹簧测力计示数为19.6N，当金属块浸没在水中后， 弹簧测力计示数为9.8N，试求：

（1）金属块的体积和密度；

（2）把金属块放在水平桌面中央时，它对桌面的压强是多大?

4. 某铸铁件在铸造时所用木模的质量是18千克，木模的密度是0.6×103千克/米3，铸铁件铸成后称得其质量是206千克，已知铸铁的密度为7.0 ×103千克/米3，问：该铸铁件中有无气泡？为什么？

5. 有一个每边长为0.1米的正方体金属块，质量为10千克，放于面积为1米2的水平桌面中央，金属块对桌面的压强是多大？如果再用12牛顿的力沿竖直方向压金属块，这时金属块对桌面的压强是多大？

5. 如图所示，边长为20厘米的正方体箱子的顶部固定有一截面积为4平方厘米的管子，现从管子上方往箱内灌水，使管中的水面高出箱子顶部30厘米，

求：（1）箱子和管子里水的总重；（2）水对箱底的压力； （3）水对箱顶的压力。

6. 将某物体挂在弹簧秤上，当物体全部浸没在水中时，弹簧秤的示数为9.8牛顿；如果此物体露出水面的体积为其总体积的4/5时，弹簧秤示数为19.6牛顿。求该物体的体积和密度。

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy! We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. To strengthen risk managemnt, ensure that the business of \o strengthened business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \prise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction

7.有一个木块，把它浸在盛满水的溢水杯中，从杯中溢出10g水，若把它尽在盛满酒精的溢水杯中，会从杯中溢出多少克酒精（酒精密度0.8×103kg/m3，水的密度1.0×103kg/m3，木块的密度0.5×103kg/m3）

8. 一个体积为0.001米3的物块放在水中漂浮在水面时，露出水面的体积为物块全部体积的 2/5 ，若将它放入某种液体中，当给它施加向下为39.2牛顿的压力时，物块将全部浸入某种液体中，求物块的密度及此种液体的密度各是多少？

9. 用扁担挑重物，扁担长1.8米，两端分别挂250牛顿和200牛顿的水桶。问要使扁担挑平，肩的位置应在哪里？（计算时不考虑扁担的重力）

10.某海军潜艇在水面匀速下潜时,潜艇质量和水舱中海水质量之和为2.06×106kg,当其下潜到300m深度时,海军战士用压缩空气把部分海水压出水舱,当6×104kg的海水被压出水舱后,潜艇漂浮在水面(海水密度为1.03×103kg/m3) 1）在海面下300m处海水对潜艇的压强是多少? 2）当潜艇漂浮在水面时它排开海水重量是多少？

3）潜艇浸没在海水时受到的浮力是多少？排开海水的体积是多少?

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy! We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysiand system handover; to strengthening BFS++, and ER, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \o.\To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \nterprise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction

11.某快艇使用的汽油热值约为4.6×107J/kg，密度约为0.7×103kg/m3，油箱容积50L，它在水中匀速航行时所受的阻力f=1400N，试求： (1)如果把油箱装满，则汽油的质量是多少？

(2)若快艇匀速行驶46km，则牵引力所做的功是多少？ (3)若快艇匀速行驶46km耗油8L，则发动机的效率为多少？

12. 用一根绳把如图所示的两个定滑轮组成一最省力的滑轮组。若每个定滑轮的重为100牛顿，绳的最大承受能力为200牛顿。（不计摩擦）

（1）画出滑轮组的绕线图；

（2）求此滑轮组能最多提起多重的物体？

（3）若在1秒钟内将500牛的重物竖直提起0.1米，求拉力的功率是多少？ （4）求提起500牛重物时，滑轮组的机械效率是多少？

提高训练：

1..将一质量为4kg的木块放入水中，静止后木块露出水面的体积为2×10-3 m3求：

（1） 木块受到的浮力（2）木块在水中的体积（3） 木块的密度

2.一木块体积为100立方厘米，密度为0.6×10kg/m3（1）当用手把它全部按如水中时，木块受到的浮力为多大？（2）松手后，木块静止时受到的浮力为多大？

3、在全面建设小康社会的热潮中，资阳市在各地农村开展了“改善农田，整

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy! We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. To strengthen risk managemnt, ensure that the business of \o strengthened business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \prise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction 理土地”的活动，其中推土机发挥了重要作用。如图所示是TY160型履带式推土机，其发动机额定功率为120kW,质量为1.5×104kg，每条履带与地面的接触面积为1.25m2。取g=10N/kg，求：（1)推土机对水平地面的压强；

(2)当推土机以额定功率进行推土作业时，在平直的场地上以5.4 km/h的速度匀速前进

了15 m，求推土机所做的功及受到的阻力。

(3)若推土机以额定功率经过10s把一块质量为6.0x103kg的石块沿斜坡推到高5m的山

坡上，则推土机的效率为多少？

4．近年来，汽车逐步走进了普通百姓的家庭．汽车出现故障后，需要进行维修．小明家的汽车发动机在维修时，工人师傅要用一个滑轮组(如右图)把车里的发动机提起来．已知发动机质量为120kg，工人拉力为400N，在10s内发动机被提起了1m．求：(g=10N/kg)

(1)发动机的重力是多少？ (2)滑轮组的机械效率是多少？ (3)工人师傅做功的功率是多少？

5.假期里，小兰和爸爸、妈妈一起参加了一个家庭游戏活动。活动要求是：家庭成员中的任意两名成员分别站在如图15所示的木板上，恰好使木板水平平衡。

（1）若小兰和爸爸的体重分别为400N和800N，小兰站在距离中央支点2m的一侧，爸爸应站在距离支点多远处才能使木板水平平衡?

（2）若小兰和爸爸已经成功地站在了木板上，现在他们同时开始匀速相向行走，小兰的速度是0.5m／s，爸爸的速度是多大才能使木板水平平衡不被破坏?

图15

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy!

We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysiand system handover; to strengthening BFS++, and ER, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \o.\To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \nterprise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction

1.某工人用滑轮组提升重物如图所示，工人用306N拉力将重为600N的重物匀速提升10m，需要时间50s，请根据提供的信息，计算两个相关的物理量。(g=10N/㎏)

2.你思考过“人在水平路面上前进时是否要克服重力做功”这个问题吗？小文同学对此进行了研究．她通过查阅资料得知，人体的重心大约位于肚脐上方2寸、脊椎前1寸处，人只要走路，其重心就必然会发生上下位置的变

质量m/kg 步距S/m 腿长l/m 时间t/s 化，重心升高就需要克服重力做功．小文假设人在正常走路时，重心在人体中的位置近似不

50 100 0．50 0．65 变，她行走了100m，有关测量数据如下表（表中的步距是指跨出每一步两脚之间的距离）

（1）小文同学注意到，当自己的前脚跨出时重心会下降，而后脚收起时重心会升高，则她每走一步，自己的重心会下降或升高多少米？

（2）小文行走100m需要克服重力做多少功？克服重力做功的功率多大？

（3）通过分析，你认为人在水平路面上通过走路来进行锻炼时，哪些因素会影响人的锻炼效果？

3.用滑轮和桶组成的装置来提水，如图所示，已知滑轮重4 N，桶重6N，桶中水重50N，现将这桶水在4s内匀速提升了5m，(不计绳重及摩摔)，求：(1)拉力F做的功和功率；(2)该装置的机械效率。

4．小华在滑冰场的水平面上5S内沿直线匀速滑行了40m。若她和滑冰鞋的总质量为50kg，每只滑冰鞋与地面的接触面积为5cm2，滑行中所受阻力为50N，根据以上数据，请你至少算出三个相关的物理量(g取10N／kg)

型号 流量 8B13 300m/h 3图

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy! We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. To strengthen risk managemnt, ensure that the business of \o strengthened business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \prise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction 5．春天农民需用水泵缺水灌溉农田，有一水泵铭牌如下： （1）水泵连续正常工作5小时，所做有用功多少J？ （2）此水泵总功率为多少？

若此水泵用一柴油机带动，假设柴油完全燃烧所释放的内能有40%

扬程 质量 效率 7

12m 111kg 80% 转化为水泵轴的机械能，则每小时消耗多少kg柴油？(柴油热值按3×10J/ kg计算，g=10N/kg)

6、上海到南京的T722次特快列车运行时刻表如下： 到站时间 发车时间 里程/km 上海 09：00 0 苏州 09：39 09：43 84 常州 10：29 10：33 165 南京 11：47 303 根据列车运行时刻表回答下列问题： （1） 计算列车由上海驶往南京全程的平均速度

（2） 列车在哪个路段运行得最快？在哪个路段运行得最慢

7、小军体重500N，他的家距离学校2400 m，他骑自行车在水平路面上以4m/s的速度匀

速直线行驶回校。有关数据在下表中列出： 自行车净重 行驶过程中轮胎与地面总接触面积 匀速行驶时的总阻力 车轮半径 轮胎承受的最大气压 250N 5×10-3 m2 30N 0.3m 2×105 Pa 求：1）行驶过程中，车对地面的压强是多大？ 2）小军骑自行车上学一程至少要做多少功？

8．如图甲中的A、B是两只用同种材料制成的体积都是1．5×10-2m3、质量都是1kg的桶． （1）在搞卫生时，你会选用哪只桶来提水，请说明理由． （2）一桶水的重力G水=？

（3）如图乙将一桶水匀速提离地面0．2m， 对水做了多少功？

（4）如图乙提水时，如果提手与手的接触面积为1×103m2，

—

0.2A 图

B 图

则手受到的压强是多大？（g取10N/kg）

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy! We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysiand system handover; to strengthening BFS++, and ER, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \o.\To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. o strengthen risk management, ensure that the business of \d business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \nterprise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction

11. 液化气炉是人们目前较普遍地使用的炉具，而电磁炉则是新一代的智能炉具。为了比

较它们的耗能费用，小胜进行了调查，得出如下两组数据： 液化气炉（用气） 电磁炉（用电） 热效率 50％ 热效率 90％ 液化气每瓶净重 15㎏ 额定电压 220V 7液化气热值 3.54×10J/㎏ 额定功率 1000W 当地液化气价格 70元／瓶 当地市电价格 0.5元／度 请问： (1)若小胜家一天所需热量相当于把50kg的水从40℃加热到100℃，则他家一天需消

3

耗多少热量?[C水＝4.2×10J/(kg·℃)]

(2)上述热量若靠电磁炉提供，需耗电多少度?若靠液化气炉提供，需燃烧多少千克的

6

液化气?(1kw·h＝3.6×10J)

(3)通过计算，你认为使用哪种炉具耗能费用更低？ （提示：液化气炉热效率是指炉子有效利用的热量与燃料完全燃烧放出的热量之比；电磁炉热效率是指电磁炉有效利用的热量与消耗的电能之比）

12.据报道，2008年北京奥运会的标志性工程——国家体育馆(“鸟巢”工程)确定采用太阳能电力这一绿色能源，去年年底在纽约交易所上市的无锡尚德太阳能电力有限公司被选中，为“鸟巢”的十二个主通道安装太阳能发电系统。

(1)若为“鸟巢”工程提供的130kW太阳能发电系统连续正常工作1h，可得到多少电

能?

3

(2)尚德公司今年的产品将达到2．4×10w的发电功率，进入全球第四名。若这些产品

提供的电能改由火力发电来提供，则每秒钟将增加约99kg的二氧化碳排放量，造

3

成大气污染。已知在通常情况下二氧化碳气体的密度为1．98kg／m。，则这些二氧化碳气体在通常情况下的体积多大?

(3)尚德公司产品的光电转化率(光能转化为电能的效率)目前在国内同行处于领先水

2

平。现有该公司生产的一块接收面积为2m的太阳能电池板，其光电转化率为17％，

3

如果太阳光照射到该电池板时每平方米面积上的辐射功率为1．Ox 10w，则它的发电功率是多大7

1．水面上浮着一物体，露出水面和浸在水里的体积之比是2∶3，则此物体密度与水的密度之比是_______；当物体浮在另一种液面上时，露出液面和浸在液内的体积之比是1∶3那么这种液体和水的密度之比是_________。 2．（三鑫双语学校）圆台形玻璃容器放置在水平桌面，开口处直径为10cm，底面直径为6cm，总高度为15cm，内装290克水，水面高为7.5cm，现向杯中投入一质量为29克的木块，木块漂浮在水面时，水面上升了0.5cm，求：（不计杯重和杯壁厚度） （1）木块所受到的浮力是多少？ （2）这时杯底的压力增加了多少？ （3）杯底对桌面的压强增加了多少?

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy! We will continue to improve the company's internal control system, and steady improvement in ability to manage and control, optimize business processes, to ensure smooth processes, responsibilities in place; to further strengthen internal controls, play a control post independent oversight role of evaluation complying with third-party responsibility; to actively make use of internal audit tools detect potential management, streamline, standardize related transactions, strengthening operations in accordance with law. Deepening the information management to ensure full communication \o constantly perfect ERP, and BFS++, and PI, and MIS, and SCM, information system based construction, full integration information system, achieved information resources shared; to expand Portal system application of breadth and depth, play information system on enterprise of Assistant role; to perfect daily run maintenance operation of records, promote problem reasons analysis and system handover; to strengthening BFS++, and ERP, and SCM, technology application of training, improve employees application information system of capacity and level. Humanistic care to ensure \To strengthening Humanities care, continues to foster company wind clear, and gas are, and heart Shun of culture atmosphere; strengthening love helped trapped, care difficult employees; carried out style activities, rich employees life; strengthening health and labour protection, organization career health medical, control career against; continues to implementation psychological warning prevention system, training employees health of character, and stable of mood and enterprising of attitude, created friendly fraternity of Humanities environment. To strengthen risk managemnt, ensure that the business of \o strengthened business plans management, will business business plans cover to all level, ensure the business can control in control; to close concern financial, and coal electric linkage, and energy-saving scheduling, national policy trends, strengthening track, active should; to implementation State-owned assets method, further specification business financial management; to perfect risk tube control system, achieved risk recognition, and measure, and assessment, and report, and control feedback of closed ring management, improve risk prevention capacity. o further standardize trading, and strive to achieve \ng to law, standardize and fair.\of performance management, to ensure that potential employees \o strengthen performance management, process control, enhance employee evaluation and levels of effective communication to improve performance management. To further quantify and refine employee standards ... Work, full play party, and branch, and members in \prise\n the of core role, and fighting fortress role and pioneer model role; to continues to strengthening \good\dership construction

lay levels cadres in enterprise development in the of backbone backbone role; to full strengthening members youth work, full play youth employees in company development in the of force role; to improve independent Commission against corruption work level, strengthening on enterprise business key link of effectiveness monitored. , And maintain stability. To further strengthen publicity and education, improve the overall legal system. We must strengthen safety management, establish and improve the education, supervision, and evaluation as one of the traffic safety management mechanism. o conscientiously sum up the Olympic security controls, promoting integrated management to a higher level, higher standards, a higher level of development. Employees, today is lunar calendar on December 24, the ox Bell is about to ring, at this time of year, we clearly feel the pulse of the XX power generation company to flourish, to more clearly hear XX power generation companies mature and symmetry breathing. Recalling past one another across a railing, we are enthusiastic and full of confidence. Future development opportunities, we more exciting fight more spirited. Employees, let us together across 2013 full of challenges and opportunities, to create a green, low-cost operation, full of humane care of a world-class power generation company and work hard! The occasion of the Spring Festival, my sincere wish that you and the families of the staff in the new year, good health, happy, happy!

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