Question

An observer at sea level does not hear an aircraft that is flying at an altitude of 7000 m until it is a distance of 13 km from the observer. Estimate the Mach number at which the aircraft is flying. In arriving at the answer, assume that the average temperature of the air between sea level and 7000 m is –10°C

Answer 1

Answer:

The answer is 2.109

Explanation:

$C = \sqrt{kRT} = \sqrt{(1.4) (287) (163)} = 325.1 m/s\\\\tan \alpha = \frac{7000}{13000} = 0.5385\\\alpha = 28.3\\\\M = \frac{1}{sen \alpha } = 2.109$