[填空题]
An airplane travels at Mach 2.3 where th c w(ltuo ad00)c8)yjje speed of sound is 310 x9wc fw;o0.)l 7gyulj74t/ls :ep zngm/s (a) What is the 4xyn7: pg7u ;e t0 wfoz l)jllgwc/s9.angle the shock wave makes with the direction of the airplane’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)
