本题目来源于试卷: ------the Beat，类别为 美国物理杯赛(Physics Bowl)
[单选题]
2.47: A car heads toward a brick walif2k+d1/zxh qvp-0ii +o1 f lzl in a crash tesx3q,mv dat -v uqg/h54t at 30 m/s. The horn is emitting a sound with frequency 250 Hz as it approaches the wall. If the air is still and the speed of sound in air is 340 m/s, what beat frequency from the horn would the d-vd hm xg,av4qtu35q/river of the car detect?
A. 0 Hz
B. 22 Hz
C. 24 Hz
D. 41 Hz
E. 48 Hz
参考答案: E
本题详细解析:
暂无
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