试卷第1页,共3页物理答案及评分标准一、二:选择题题号123456789101112答案CADCDBABCCDACBCAB三、解答题13.84.5080.0无影响......................................................................每空2分14.C0.388斜面倾角过大2M.......................................................每空2分15.(9分)【答案】(1)25N,15N;(2)0.25【详解】(1)对O点进行受力分析可知ocos37DTmg..............................................................................................................2分osin37DBTT.................................................................................................................2分代入数据可得DO,BO线的拉力大小分别为25NDT...........................................................................................................................1分15NBT............................................................................................................................1分(2)由于整个系统恰好处于静止状态,则ATMg..........................................................................................................................2分解得0.25.....................................................................................................................1分16(9分)(1)212hgt..............................2分得:2st........................................1分vgt.........................................2分得:20m/sv......................................1分(2)由题意知,窗口的高度为:2mh2112hvtgt......................................2分19msv......................................1分17(9分)(1)设最大速度为mv,匀速阶段所用时间为2t,根据题意有:1212sttt................................................................................................................1分m1116m2vxt..............................................................................................................1分试卷第2页,共3页2m264mxvt......................................................................................1分联立解得:14st..............................................................................................................................1分m8m/sv......................................................................................................................1分(2)小明匀加速运动阶段的加速度大小为2m12m/svat.............................................................................................................1分根据牛顿第二定律可得,对m有°°cos37sin37Nfmg............................................................................................1分°°sin37cos37Nfma.............................................................................................1分联立解得:9.2NN.....................................................................................................................1分18(11分)解:(1)设物块的加速度大小为a1,由牛顿第二定律有11mgma.......................................................................................................................1分解得:2112m/sag.............................................................................................................1分因为2s时达到共速,此时速度大小:10112m/svvat........................................................................................................1分长木...
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