设加速时间t1 速度vv=a1t1=a2(t-t1)t1=a2t/(a1+a2)v=a1a2t/(a1+a2)s=vt/2=1/2a1a2t^2/(a1+a2)运动总位移s=1/2a1a2t^2/(a1+a2)