Motion requires the standard graphics card found in any Mac Pro, MacBook Pro, iMac Intel Core Duo, Power Mac G5, iMac G5, a 1.25 GHz or faster PowerBook G4, or a 1.25 GHz or faster flat-panel iMac.
yes it will run, but you will become rather frustrated with the "speed" Motion Is built around the assumption it has a dedicated Graphics card with dedicated Ram.
64Mb of shared ram that the GMA 950 in the macbook is very limiting It not designed for this kind of intensive work.