发布时间:2025-01-29 12:04:43
对O点受力分析,抓住两根绳的合力等于物体的重力,大小和方向都不变,OB绳拉力方向不变,根据平行四边形定则得,如图,知OA绳上拉力大小先减小后增大.
当OA跟OB垂直时,即与OC成60°角时,拉力最小.故AD正确,B、C错误.
故选:AD.
我选的洗手盆是一米长,宽是五十,坐便器是四十工分宽长是七十五,我卫生间总长是一米八,洗手盆跟坐便器
2025-01-29 12:04:43 2025-01-29 12:04:43 2025-01-29 12:04:43 2025-01-29 12:04:43 2025-01-29 12:04:43在宿舍里贴无纺布壁纸要想粘合度高又不弄脏床有什么简单的方法吗
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