A:f1向左,f2向右,大小都等于1.2 N
B:f1向右,f2向左,大小都等于1.2 N
C:f1向左,大小为2 N,f2为零
D:f1向右,大小为3 N,f2为零
b____e 蜜蜂
——I can hardly believe my eyes. Is that you, Lucy?——Yes. It has been almost 20 years______ we were together.
如图甲所示中,一圆柱体置于水平桌面上,其体积为160cm3.用一弹簧测力计拉着这个物体从图所示位置开始向上缓慢提升,其示数F 与弹簧弹簧测力计顶端上升高度h之间的关系如图乙所示.求: