初中物理、一辆汽车朝山崖行驶、离山崖720m处鸣笛、继续行40m听到回声、求行驶速度

2024-12-19 10:19:47
推荐回答(5个)
回答1:

空气中音速V=340m/s
司机听到的回声传行的路程 S=720*2-40=1400米
用时 T=S/V=1400/340 秒
这段时间汽车行走了40m
故,车速V'=S'/T=40/(1400/340)=9.71m/s

回答2:

从鸣笛到听到回声,声音传播的距离为2*720-40=1400m
已知声速340,可求出声音传播的时间为1400/340=4S
汽车行驶时间也是4S,所以速度为40/4=10m/s

回答3:

大约是10M/S
因为声速为340M/S 声音行驶了1400m
在这段时间,汽车行驶了40M
所以答案是10m/s

回答4:

声音一去一回之间,声音走了720 + (720 - 40) m,汽车走了 40m
设声速s=340m/S,则汽车速度
40/[(720+720-40)/340] = 9.7143 m/S
折算成Km/H为 35千米/小时

回答5:

设速度为V,行驶40米的时间为t=40/v,
则在这段时间内声音传播的距离为720*2-vt=340*t
把一式带入二式。得解。

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