x'sx-ut x=+ ut t=t t= t S系→>S'系 S'系→》S系 2.伽利略速度变换 dx' d(x-ut =0.-L dt dt dt o-u U=0+L U .=7x  = x − ut y  = y z  = z t = t 2. 伽利略速度变换 x = x  + ut y = y  z = z  t = t t x ut d d( − ) = u t x = − d d t x x    = d d v v x = vx − u vy = vy  vz = vz  vx = v x + u vy vy =  vz vz =  = vx − u S系→ S系 S系→ S系