Answer: Half.
- A Same
- B Half
- C Double
- D One-fourth
Correct answer: B. Half
Explanation: g' = G(2M)/(2R)2 = 2GM/4R2 = GM/(2R2) = g/2. Surface gravity is half of Earth.
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.