Question

以8km/h的速度沿直线均速驶向一高山崖壁的汽车,驾驶员鸣笛后经4s听到从崖壁反射回来的声音.求鸣笛时汽车与崖壁的距离.

Answer 1

已知；v空=340m/s,v车=8km/h=8*1/3.6m/s=20/9m/s,t=4s

求；S鸣笛时汽车与崖壁的距离=?

解；S+S-v车t=v空t

2S-20/9m/s*4s=340m/s*4s

2s=12320/9m

s=6160/9m约等于684.44m

答；鸣笛时汽车与崖壁的距离约为684.44m.