Considering two rocks of equal mass on the Moon, one on the near side and one on the far side, we can think of the tidal force as the difference between the gravitational force by Earth on the near-side rock and on the far-side rock. If the Moon were orbiting at 3 times its present distance from Earth, what would the tidal force be, compared to its present value?

Question

Quizplus · Accepted Answer

The tidal force decreases with the cube of the distance, so if the Moon were orbiting at 3 times its present distance, the tidal force would be (1/3)^3 = 1/27 of its present value. Therefore, the answer is D.

Considering Two Rocks of Equal Mass on the Moon, One