39. A supersonic jet fighter flies horizontally at a constant altitude of 3400 m with a speed of Mach 1.25. Assuming the speed of sound is 340 m/s, how much time will elapse after the jet passes directly over an observer before the shock wave (sonic boom) reaches them?
(A) 4.00 s
(B) 6.00 s
(C) 7.50 s
(D) 8.00 s
(E) 10.0 s

答案:登入後查看
統計: 尚無統計資料