单摆a= T=2 mghT=2丌, IV=2兀 mgh 复摆O V mgh 3、位相和初位相x=Acos(a+g0) a+φo-位相,决定谐振动物体的运动状态 v=- 0A sin(ot+φo) q是t=0时刻的位相纫位相 t=0时x0= AcoS vo=-A@ sino 0单摆 g l T = 2 l g   2 1 = l g  = 复摆 mgh I T = 2 I mgh   2 1 = I mgh  = v Asin( t ) = −  +0 0 是t =0时刻的位相—初位相 0 0 0 t = 时 x = Acos 0  0 v = −A sin 0 0 0 x v tan   = − 3、位相和初位相 x Acos( t ) =  +0 t + 0 —位相，决定谐振动物体的运动状态