因为4s内位移为0,所以3.5s时位移最大,匀变速运动：第2s内位移大小=第6s内位移大小3s-3.5s内的位移:2.5s-3s...:2s-2.5s...:1.5s-2s...:1s-1.5s...=1:3:5:7:9所以第2s内位移(=第6s内位移）:第3s内位移:3s-3.5s内位移=...