Orbital and Escape Velocity

Orbital velocity: minimum velocity for satellite to orbit (gravitational force = centripetal force): v_o = √(GM/r) = √(gR²/r). For orbit just above Earth: v_o ≈ 7.9 km/s. Escape velocity: minimum velocity to escape Earth's gravity: v_e = √(2GM/R) = √(2gR) ≈ 11.2 km/s = √2 × v_o.