a) $3.41 \ imes 10^{-5} \ extrm{ m/s}^2$\r\rb) $3.33 \ imes 10^{-5} \ extrm{ m/s}^2$. These are nearly equal, which is expected since the moon is providing the centripetal force which causes the Earth's center to rotate about the center of mass of the Earth-Moon system.