某同学把耳朵贴在长钢管的一端，乙同学在另一端敲一下钢管，想让甲同学听到两次声音，钢管至少多长？
\u7269\u7406\u9898\uff1a\u7532\u540c\u5b66\u628a\u8033\u6735\u8d34\u5728\u957f\u94c1\u7ba1\u7684\u67d0\u4e00\u7aef,\u4e59\u540c\u5b66\u5728\u53e6\u4e00\u7aef\u6572\u4e00\u4e0b,\u5982\u679c\u60f3\u8ba9\u7532\u540c\u5b66\u542c\u5230\u4e24\u6b21\u76f8\u58f0,L=(V2-V1)t=(5200-340)x0.1=486m
\u94a2\u7ba1\u81f3\u5c11\u5e94\u6709486m\u957f
(5200-340)*0.1=486(m)
\u5373\u56de\u58f0\u4e0e\u539f\u58f0\u95f4\u9694\u57280.1\u79d2\u4ee5\u4e0a
t气 - t铁 =0.1s
L /340m/s- L/5200m/s=0.1s
L=36.8m
答：钢管至少36.8米
哪点不明可追问
绛旓細棣栧厛锛屾槑纭竴鑸儏鍐典笅锛屽０闊冲湪绌烘皵鍜岄搧涓殑浼犳挱閫熷害鍒嗗埆鏄:340绫/绉掋5000绫/绉掞紱鎺ヤ笅鏉ワ紝璁閽㈢闀垮害涓篨锛屽垯:Xm/340m/s- Xm/5000m/s=0.7s X*1/340-X*1/5000=0.7 X*(1/340-1/5000)=0.7 X*0.00274=0.7 X鈮255.47 鎵浠ラ搧绠＄害闀255绫 ...
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绛旓細璁鹃搧绠＄殑闀垮害涓猴細L,鏁插嚮澹伴氳繃閾佸拰绌烘皵鍒嗗埆浼犲埌浜鑰,鏃堕棿鐩搁殧0.7S,L /340m/s- L/5100m/s=0.7s L=255M 绛 閽㈢闀255绫
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