一只质量为m的蚂蚁,在半径为R的半球形碗内爬行,在距碗底高R/2的A点停下来,则蚂蚁在A点受到的摩擦力大小为

一只质量为m的蚂蚁,在半径为R的半球形碗内爬行,在距碗底高R/2的A点停下来,则蚂蚁在A点受到的摩擦力大小为
一只质量为m的蚂蚁,在半径为R的半球形碗内爬行,在距碗底高R/2的A点停下来,则蚂蚁在A点受到的摩擦力大小为

一只质量为m的蚂蚁,在半径为R的半球形碗内爬行,在距碗底高R/2的A点停下来,则蚂蚁在A点受到的摩擦力大小为
答案：mg*√3/2.
蚂蚁受到三个力：重力、支持力和摩擦力.三个力合力为零,支持力与摩擦力垂直,摩擦力与重力夹角30度,利用平行四边形定则可解.

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用物理知识解答，蚂蚁受三个力，自身重力，碗的支持力，摩擦力，三力平衡。将重力分解为两个力，其中一个与重力平衡，即为摩擦力。另一种做法，把摩擦力与支持力合起来，与重力，大小相等，方向相反，利用蚂蚁自身重力与三角知识解吧