一、平衡力与相互作用力例1踢出去的足球在水平草地上滚动,在下面列举的各对力中,属于平衡力的是().A.球对草地的压力和草地对球的支持力B.球所受的重力和球所受的摩擦力C.球所受的重力和球对草地的压力D.球所受的重力和草地对球的支持力 First, the balance of forces and the interaction of Example 1 kicked out of the football rolling on the level of grass, in the following list of the opposing forces, the balance of power is () A. The pressure of the ball on the grass and turf on the ball support B. the ball suffered by the gravity and the friction suffered by the ball C. the ball suffered by the ball and the pressure on the grass D. the ball suffered by the grass and grass on the ball support