Analogous to Eq. [8-7], the magnitude of the acceleration of gravity on the moon is given by Taking the ratio of this to Eq. [8-7], we get gM_mM( rE)2 g ma rM 1 2 0.0122( m) 0.164 Hence, gM = 0.164g = 0.164(9.80 m/s2) = 1.60 m/s2, signi- cantly smaller than the gravitational acceleration on Earth