(1)V2-V1= at 10-20=-0.5t t=20s
位移:A:S1=V1t + at²/2 = 20 x20 - 0.5x20²/2 = 300m
B:S2=V2t = 10x20=200m
(2) 不相撞:S1≤S2+s 300 ≤ 200+ s
满足100m≤s
(1)V2-V1= at 10-20=-0.5t t=20s
位移:A:S1=V1t + at²/2 = 20 x20 - 0.5x20²/2 = 300m
B:S2=V2t = 10x20=200m
(2) 不相撞:S1≤S2+s 300 ≤ 200+ s
满足100m≤s