Answer: 6.67 x 10 -11 N m 2 /kg 2.
- A 6.67 x 10<sup>-11</sup> N m<sup>2</sup>/kg<sup>2</sup>
- B 9.8 m/s<sup>2</sup>
- C 6.67 x 10<sup>-11</sup> N/m<sup>2</sup>
- D 9.8 N/kg<sup>2</sup>
Correct answer: A. 6.67 x 10<sup>-11</sup> N m<sup>2</sup>/kg<sup>2</sup>
Explanation: G = 6.674 x 10<sup>-11</sup> N m<sup>2</sup> kg<sup>-2</sup> (Universal Gravitational Constant).
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.