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 walnf k-.*6td1q0dew:rpow u qw3 v9;t yql in a crash testbg;d th,t0f)tcji*a5 at 30 m/s. The horn is emitting a s;0jc, ta5h*dtg ibt) found 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 driver 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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