Answer: Ocean bulges on both sides facing and opposite Moon.
- A Ocean tides mainly on the side facing Moon under typical conditions
- B Ocean bulges on both sides facing and opposite Moon
- C No effect on Earth according to standard textbooks
- D Mainly earthquakes in general practice as frequently described
Correct answer: B. Ocean bulges on both sides facing and opposite Moon
Explanation: Tidal forces stretch Earth along the Moon-Earth axis, creating bulges on both the near AND far sides. Hence two high tides per day.
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.