Answer:
Step-by-step explanation:
mach number is ratio of speed with respect to speed of sound .
speed of aircraft = 936 m /s
speed of sound at 65500 ft = 295 m /s
mach number = 936 / 295 = 3.17
velocity of sound at - 145 degree and in hydrogen gas .
velocity of sound


= 729 m /s
mach number
= 936 / 729 = 1.28
velocity of sound at - 223 degree and in nitrogen gas .
velocity of sound


= 122 m /s
mach number
= 936 / 122 = 7.67