最新《b摩擦力习题》PPT课件教学讲义ppt课件.ppt

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1、《b摩擦力习题》PPT课件15.质量为2kg的物体静止在水平地面上，如图7所示，物体与地面间的动摩擦因数为0.5，最大静摩擦力与滑动摩擦力视为相等，给物体一水平推力．(取g＝10N/kg)(1)当推力大小为5N时，地面对物体的摩擦力是多大？(2)当推力大小为12N时，地面对物体的摩擦力是多大？图716．如图8所示，轻质弹簧的劲度系数k＝20N/cm，用其拉着一个重为200N的物体在水平面上运动，当弹簧的伸长量为4cm时，物体恰在水平面上做匀速直线运动，求：(1)物体与水平面间的动摩擦因数．(2)当弹簧的伸长量为6cm时，物体受到的水平拉力多大？这时物体受到的摩擦力有多大？(

2、3)如果物体在运动的过程中突然撤去弹簧，而物体在水平面上能继续滑行，这时物体受到的摩擦力多大？英语句子成分分析长难句分析Theworkerswhogetsapromotion,thestudentwhosegradesimprove,theforeignerwholearnsanewlanguage---alltheseareexamplesofpeoplewhohavemeasurableresultstoshowfortheirefforts.长难句分析Asfamiliesmoveawayfromtheirstablecommunity,theirfriendsofma

3、nyyears,theirextendedfamilyrelationships,theinformalflowofinformationiscutoff,andwithittheconfidencethatinformationwillbeavailablewhenneededandwillbetrustworthyandreliable.关系词填空1.Theman_______isshakinghandswithmyfatherisapoliceman.2.The engineer, _______ leg was badly hurt, was quickly sen

4、t to hospital.3.TheGreatWallistheplace____almostalltouristswouldliketovisitwhentheycometoBeijing.4.Sailingacrosstheoceanalonewasanachievement_____tookcourage.5.Thewonderfulmoment,_____wehadbeenexpectingforyears,finallycame.6.Therewasatreeinfrontofthehouse,_____ownerwasseensittingunderit,en

5、joyingtheshade.7.Those______wanttogotothemuseummustbeattheschoolgateat7tomorrowmorning.8.Thegirl______theteacheroftenpraisesisourmonitor.9.Doyouknowthewasteland_____theyusedtoplayhasbeentransformedintoathemepark?10.I still remember the time ______ I joined the League.11.Afterthefireinhisho

6、use,theoldcaristheonlything______heowns.12.Theytalkedaboutthepersonsandthings_____theyrememberedatschool.13.YesterdaywevisitedtheWestLake__________Hangzhouisfamous.14.Thenaughtyboymadeaholeinthewall_________hecouldseewhatishappeningoutside.15.Allofusdislikedtheway_________Tomsettledthemath

7、sproblem.16.Idon’tunderstandtheway________theteacherexplainedtome.17.Ivisitedthevillage________manychildrencouldn’tgotoschoolbecauseofpoverty.18.We’dbetterfixadate_______wewillpracticespeakingEnglishnextweek.19.Canyoutellmethereason______youwerelateforschool?2