Answer: 9.8 m/s2.
- A 9.8 m/s2
- B 8.9 m/s2
- C 10.8 m/s2
- D 6.7 m/s2
Correct answer: A. 9.8 m/s2
Explanation: g = 9.8 m/s2 approximately. For calculations, g = 10 m/s2 is often used.
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.