Question

The illustration below shows Earth and the moon. The arrows represent the gravitational attraction between the two.

Image

When is the gravitational attraction between Earth and the moon the strongest?

A.
when the moon appears full in the night sky

B.
when Earth and the moon are the closest to one another

C.
when Earth and the moon are the farthest apart from each other

D.
when North America faces the moon in the night sky

Answer 1

B. when Earth and the moon are the closest to one another.

Gravitational force follows Newton's law F = G m1 m2 / r^2, so the force is strongest when the separation r is smallest (perigee).