✔ 最佳答案
For the pressure and temperature 4000m above sea level,
Pb = 101325 (pascals)
Tb = 288.15 (kelvins)
Lb = -0.0065 (kelvins per metre) according to ICAO
h = Height above sea level (metres)
R = Universal gas constant: 8.31432×10^3 N·m / (kmol·K)
g0 = Gravitational constant (9.80665 m/s)
M = Molar mass of Earth's air (28.9644 g/mol)
T = temperature = Tb + Lb * h = 288.15 - 0.0065 * (4000)
T = 262.15 K = - 11 deg C
P = pressure = Pb * [ Tb / [Tb + Lb * h] ] ^ [(g0 * M) / (R * Lb)]
P = 101325 * [ 288.15 / 262.15 ] ^ [(9.80665 * 28.9644) / (8314.32 * -0.0065)]
P = 101325 * [ 288.15 / 262.15 ] ^ (-5.25588)
P = 61640.24 pascals