如图6所示,轻质杠杆OA可绕O点转动,杠杆长0.2m,在它的A端挂一重20N

如图6所示,轻质杠杆OA可绕O点转动,杠杆长0.2m,在它的A端挂一重20N的物体G,若在杠杆上的中点B处施加最小的力F,使杠杆在水平位置平衡,则力F的方向应__________,大小为___________N

答案

竖直向上        40

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