The center of the moon is 0.0026 au (3.890 x 10^8 m) from the center of the earth and has a relative mass of 0.0123. locate the cm of the earth-moon system with respect to the center of the earth. with respect to the center of the moon. find the ratio of orbital velocities of the earth and moon about the cm of the system. if the orbital velocity of the moon is 1012 m/s, what is the approximate orbital velocity of the earth about th