Answer: g(1-d/R).
- A g(1-d/R)
- B g(1-2d/R)
- C g(1-d<sup>2</sup>/R<sup>2</sup>)
- D g*d/R
Correct answer: A. g(1-d/R)
Explanation: g at depth d = g(1 - d/R). At center (d=R), g = 0. At surface (d=0), g = g.
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.