Answer: Faster.
- A Slower
- B Faster
- C Same speed
- D Speed depends on mass
Correct answer: B. Faster
Explanation: From Kepler's third law, T2 proportional to r3 means inner planets (smaller r) have smaller T (faster orbital speed).
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.