设两端S之间的速度为v,则：S=vt1-1/2at1^2,即：v=(S+1/2at1^2)/t1S=vt2+1/2at2^2,即：v=(S-1/2at2^2)/t2所以：(S+1/2at1^2)/t1=(S-1/2at2^2)/t2(S+1/2at1^2）*t2=(S-1/2at2^2)*t11/2at1t2(t1+t2)=S(t1-t2)a=2S(t1-t2...