Answer this physics question?

Question

What speed must a 20 kg projectile be launched from earth to just reach a height of 250 km above the surface of the Earth and stop?

mass of earth = 5.98X 10^24

radius of earth = 6.38 X10^6

G=6.67X10^-11

Answer 1

V = √(2gRh/(R+h))

where R = radius of earth, g = GM/R², h = height above surface

V = √(2*9.81*6.38E6*250E3/(6.38E6+250E3)) = 2171 m/s