Answer: raph : rper.
- A raph : rper
- B rper : raph
- C raph2 : rper2
- D rper2 : raph2
Correct answer: A. raph : rper
Explanation: By conservation of angular momentum: m x vper x rper = m x vaph x raph. So vper/vaph = raph/rper.
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.