[填空题]
An airplane travels at Myqd1bnjb:6a hom3c0 *ach 2.3 where the speed of sound is 31p97cl js+ti 7.f kn5b/bl2gt f0 m/s (a) What is the angle the shock wave makes with the direction of the airslk7jtf +9p2 l5bgbf7.t/ incplane’s motion? $^{\circ} $
(b) If the plane is flying at a height of 7100 m, how long after it is directly overhead will a person on the ground hear the shock wave? $\approx$ s (Round to the nearest integer)