Sarah's hair was out of her face and held back by a hair slide.

萨拉脸上没有头发，而是用小发夹将头发扎在脑后

If I go then one hair further, it will start to slide, and so that's the case when this equals mg sine theta, mg and so you lose your mg, and you find that mu s equals tangent theta.

如果在向上一点，就会下滑，当这个等于mgsinθ,时，就会发生，所以约掉，会发现mu，s=tanθ

Teach you apologize, son shirt, slide down slides, and tell you the clothes, comb the hair hair, pinch the nose.

教你系鞋带、扣扣子、溜滑梯、教你穿衣服、梳头发、拧鼻涕。

Teach you apologize, son shirt, slide down slides, and tell you the clothes, comb the hair, pinch the nose.

教你系鞋带、扣扣子、溜滑梯、教你穿衣服、梳头发、拧鼻涕。