设每段所用时间为T,则各段位移分别为
s1=aT^2/2
s2=a(2T)^2/2-aT^2/2=3aT^2/2
s3=a(3T)^2/2-a(2T)^2/2=5aT^2/2
则s1:s2:s3=1:3:5