Answer: Polar radius is smaller so closer to center.
- A The polar radius of Earth is larger than the equatorial radius
- B Earth's rotation alone increases g everywhere uniformly
- C Polar radius is smaller so closer to center
- D Earth's mass distribution is concentrated more heavily near the poles
Correct answer: C. Polar radius is smaller so closer to center
Explanation: Earth is oblate: polar radius is smaller. Since g = GM/r<sup>2</sup>, smaller r at poles means larger g.
g is maximum at Earth's surface; going up, it falls off as 1/r² (inverse-square); going down, it falls off linearly with depth (since only the mass enclosed within radius r contributes), reaching zero at the centre.
Concept context
Universal gravitation, orbital mechanics, gravitational potential, and escape velocity.