Answer: 1/6.
- A 1/2
- B 1/4
- C 1/6
- D 1/10
Correct answer: C. 1/6
Explanation: Moon's gravity is about 1/6 of Earth's gravity. So weight on Moon = W<sub>earth</sub> / 6.
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.