§1.3加速度 v(t △U v(t dd dt dt2 U(计△t) rt) (汁+△t) (计△t a=arxtavy+a2Z dvx dv d .= dt dt dt 2 2 = +a+a214 §1.3 加速度 t v a d d   = a a x a y a z x y z = ˆ + ˆ + ˆ  x r(t+Δt ) r(t) y z 0 v (t ) v (t+Δt ) Δv v (t ) v (t+Δt ) 2 2 t r d d  = t v a t v a t v a z z y y x x d d d d d d = , = , = 2 2 2 a = ax + ay + az