已知动滑轮总重100N,物体重G=1200N,绳子能承受的最大拉力为300N,请在图上画出滑轮组的绕线方法。根据你的绕法,绳子自由端的实际拉力为多少?(不计绳重及摩擦)
,。
We were all very much attracted by the beautiful scenery________we set foot in the village. [ ]
A. quickly
B. suddenly
C. finally
D. immediately
每题的备选项中,只有1个最符合题意。
电缆必须悬挂,在水平巷道或倾角在( )以下的井巷中,电缆应用吊钩悬挂。
A.30°
B.45°
C.60°
D.90°