m/s,由公式s=vt得:
列车鸣笛后2s时间内声音传播的路程为:
s1=v1t=340m/s×2s=680m,
2s内列车前进的距离为:
s2=v2t=
m/s×2s=
m,
∵2s=s1 s2,
列车鸣笛时距隧道口距离为:
s=
=
m/s,由公式s=vt得:
列车鸣笛后2s时间内声音传播的路程为:
s1=v1t=340m/s×2s=680m,
2s内列车前进的距离为:
s2=v2t=
m/s×2s=
m,
∵2s=s1 s2,
列车鸣笛时距隧道口距离为:
s=
=
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