Acceleration: is it"s speed changing? choose frame of reference! Vectors: choose axis (2d, 3d) and locate point with reference to reference! break down into components (make direction clear)! In general: |v + w| |v| + |w|! Position:! need reference point! need direction and distance or vector! 4km 5 degrees [s of w] ! or ! Examples: if initial and nal positions are! what is the magnitude of displacement? (see notebook for solution)! Rate of change of position during some time interval! Rate of change of velocity during some time interval! Change in velocity during an in nitesimally short period of time! Let start time be ti and nish time be tf : t= tf -ti! Let start velocity be vi and nish velocity be vf : v= vf - vi! Displacement during a in nitesimally short period of time:! Time interval has to be small enough that the velocity measurement is not changing!