Answer:

Explanation:
By Snell's law we know at the left surface




now we have


now on the other surface we know that
angle of incidence = 

so again we have

so we have


also we know that


By solving above equation we have

Answer:
a) - 72.5°c
b) pressure = 3625.13 Pa
c) density = 0.063 kg/m^3
d) it is a subsonic aircraft
Explanation:
a) Determine Temperature
Temperature at 19.5 km ( 19500 m )
T = -131 + ( 0.003 * altitude in meters )
= -131 + ( 0.003 * 19500 ) = - 72.5°c
b) Determine pressure and density at 19.5 km altitude
Given :
Po (atmospheric pressure at sea level ) = 101kpa
R ( gas constant of air ) = 0.287 KJ/Kgk
T = -72.5°c ≈ 200.5 k
pressure = 3625.13 Pa
hence density = 0.063 kg/m^3
attached below is the remaining part of the solution
C) determine if the aircraft is subsonic or super sonic
Velocity ( v ) =
=
= 283.8 m/s
hence it is a subsonic aircraft
<u>We are given:</u>
Mass of the rocket = 10 kg
Weight of the Rocket = 100 N
Upward thrust applied by the rocket = 400 N
<u>Net upward force on the rocket:</u>
We are given that gravity pulls the rocket with a force of 100 N
Also, the rocket applied a force of 400N against gravity
Net upward force = Upward thrust - Force applied by gravity
Net upward force = 400 - 100
Net upward force = 300 N
<u>Upward Acceleration of the Rocket:</u>
From newton's second law:
F = ma
<em>replacing the variables</em>
300 = 10 * a
a = 30 m/s²