1.车头到达桥头时经过时间0.5a(t1)^2=200,则t1=20s,Vo=20m/s:整个火车要通过全桥需行驶250m,所以Vot2+0.5a(t2)^2=250m,t2=10s(或50s不合)
2.需行驶车长100m,所以Vot3+0.5a(t3)^2=100m,t3=4.5s.
1.车头到达桥头时经过时间0.5a(t1)^2=200,则t1=20s,Vo=20m/s:整个火车要通过全桥需行驶250m,所以Vot2+0.5a(t2)^2=250m,t2=10s(或50s不合)
2.需行驶车长100m,所以Vot3+0.5a(t3)^2=100m,t3=4.5s.