∑F=ma,=m dt 直角坐标系中:〈 ∑F=ma,=m v, ∑F:=ma =m dv dt F mai +ma,j+ma,k ∑F=ma,=m v 自然坐标系中: ∑=ma,=m F ma mae ma e 正觉不美返回退 上页 下页 返回 退出 d d y y y v F ma m t = = d d x x x v F ma m t = = d d z z z v F ma m t = = 直角坐标系中: t t 2 n n d d v F ma m t v F ma m = = = = 自然坐标系中: F ma i ma j ma k = + + x y z F ma ma e ma e = = + t t n n