Advanced — Escape from OrbitHardQuestion 30777
Question
To escape Earth's gravity from a circular orbit at radius r (speed v₀ = √(GM/r)), the speed must be increased to:
- A√(2GM/r) = √2 v₀Correct
- B2v₀
- Cv₀ + √(gR)
- Dv₀/√2
Correct answer
√(2GM/r) = √2 v₀
Explanation
Escape speed from any point at radius r: v_e = √(2GM/r) = √2 × √(GM/r) = √2 × v_orbital. The spacecraft must increase speed by factor √2 (increase of about 41%).