The center-to-center distance between Earth and Moon is 384400 km. The Moon completes an orbit in 27.3 days. (b) If gravity were switched off, the Moon would move along a straight line tangent to its orbit, as described by Newton's first law. In its actual orbit in 1.00 s, how far does the Moon fall below the tangent line and toward the Earth? part (a) was asking for the Moon's orbital speed which was 1024 m/s. for part (b) my question is I don't know what equation to use to solve for this. All i know is that I need to use centripetal acceleration but when? thanks and i hope you can help~!!