已知一质点作简谐振动振动方程为=0.02cos (50pi t-dfrac (pi )(3)),则该质点在t=2s时的速度v=( )=0.02cos (50pi t-dfrac (pi )(3))=0.02cos (50pi t-dfrac (pi )(3))=0.02cos (50pi t-dfrac (pi )(3))=0.02cos (50pi t-dfrac (pi )(3))

已知一质点作简谐振动,振动方程为 x=0.02-|||-cos (50pi t-dfrac (pi )(3)), 则该质点在 t=2s 时的加速度约-|||-为

一质点作简谐振动，其振动方程为=6.0times (10)^-2cos (dfrac (1)(3)pi t-dfrac (1)(4)pi )(SI)（1）当=6

两简谐振动的振动方程分别为_(1)=3cos (2pi t-dfrac (pi )(3)), _(2)=4cos (2pi t+dfrac (pi )(6))单

两分振动方程分别为_(1)=3cos (50pi t+0.25pi )cm 和 _(2)=4cos (50pi t+0.75pi )cm则它们合振动的表达式为（

某质点参与_(1)=10cos (pi t-dfrac (pi )(2))cm 及 _(2)=20cos (pi t+dfrac (pi )(2))cm两个同方

【题目】某质点参与 _(1)=5cos (pi t-dfrac (pi )(2))cm 及-|||-_(2)=5cos (pi t+dfrac (pi )(2)

5.一质点同时参与两个在同一直线上的简谐振动:-|||-_(1)=0.04cos (2pi t+dfrac (pi )(2))m, _(2)=0.03cos (

已知某质点作简谐振动，其振动方程为=0.6cos (5pi t+0.8pi ),则初相位等于___=0.6cos (5pi t+0.8pi )。已知某质点作简谐

已知一质点作简谐振动振动方程为=Asin (omega t+dfrac (pi )(3))则其初相位为=Asin (omega t+dfrac (pi )(3)

一个质点作简谐运动,其运动方程为=0.05cos (pi t-pi )(SI) =dfrac (3)(2)s则其在时的速度为=0.05cos (pi t-pi