第二章相互作用第二章相互作用1/532/533/534/535/536/537/538/539/5310/5311/5312/5313/53匀速直匀速直线线运运动动14/53FmgF1FfF2FNmg15/53其余两个力其余两个力协协力力其余几个力其余几个力协协力力大小相等大小相等,方向相反方向相反16/5317/5318/5319/5320/5321/5322/5323/5324/5325/5326/5327/5328/5329/5330/5331/5332/5333/5334/5335/5336/5337/5338/5339/5340/5341/5342/5343/5344/5345/5346/5347/5348/5349/5350/5351/5352/5353/53