問題詳情
43. When an ambulance passes in front of an observer, the sound frequency is 440 Hz when theambulance is approaching, and the frequency drops to 400 Hz when the ambulance is movingaway. What is the speed of the ambulance? (Assume the speed of sound is 345 m/s at that time.)
(A) 13.8 m/s
(B) 14.0 m/s
(C) 14.4 m/s
(D) 15.4 m/s
(E) 16.4 m/s
參考答案
答案：E
難度：計算中-1
書單：沒有書單，新增
用户評論
【用戶】面試倒楣鬼-22幸運上後西
【年級】大一下
【評論內容】(345+v)/(345-v) = 440/400,快速算法,40約是400的10%得2v為345的10% , v~= 17.25 最接近(E), 此題選項差距小才比較會有困擾
【用戶】面試倒楣鬼-22幸運上後西
【年級】大一下
【評論內容】(345+v)/(345-v) = 440/400,快速算法,40約是400的10%得2v為345的10% , v~= 17.25 最接近(E), 此題選項差距小才比較會有困擾