Acceleration due to Gravity

g = GM/R² (at Earth's surface). g = 9.8 m/s² at surface. Variation: g decreases as height increases (g_h = g(R/(R+h))²). g decreases inside Earth (g_d = g(1-d/R)). g is maximum at poles, minimum at equator (due to rotation and shape). g on Moon = g_Earth/6 ≈ 1.6 m/s².