[mahmoud khodary]

g = 9.81 - 3.32*10^-6* h v = 900 km/h = 900 *1000/3600 = 250 m/ s
h = 10 km = 10000 m w = 40 kN = 40000 N
g = 9.81 - 3.32*10^-6 * 10000 = 9.7768 m/ s^2

K E = 0.5 * m * V^2
m = w/g =40000/9.7768 = 4091.3 kg
K E = 0.5 * 4091.3 *250^2 = 127.85*10^6 Joule

P E = w * h = 40000 * 10000 = 400*10^6 Joule