A lunar month is about 28 days. If the Moon were closer to Earth than it now is, the lunar month would be
A)less than 28 days,
B)more than 28 days,
C)still 28 days,
Mainly because
D)centripetal force would lessen with decreased distance.
E)a closer Moon means an increase in both gravitational force and speed, which in a smaller orbit means shorter time.
F)orbital speed about the center of mass of Earth-Moon system is not dependent upon the distance between Earth and Moon.
G)of tidal friction.

Question

Quizplus · Accepted Answer

E) A closer Moon means an increase in both gravitational force and speed, which in a smaller orbit means shorter time. This is due to Kepler's laws of planetary motion, where the orbital period decreases as the orbital radius decreases, assuming the mass of the central body (Earth, in this case) remains constant.

A Lunar Month Is About 28 Days