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a= ()-|||-(A) /(s)^2-|||-(B) -250m/(s)^2-|||-(C) sqrt (3)m/(s)^2-|||-(D) -250sqrt (3)m/(s)^2

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 (5

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

t=0.2s 时,P、Q两质点加速度相同-|||-C,P质点的振动方程为 =2sin (dfrac (5pi )(3)t-dfrac (pi )(6))(cm)

6.5178:一质点沿x轴作简谐振动,振动方程为 =4times (10)^-2cos (2pi t+dfrac (1)(3)pi )(S1) t=-|||-0

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

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)

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

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

一个作简谐振动的质点，其运动方程为x=5cos(({pi )over(2) }t+({pi )over(2) } )(cm)，则振动的振幅A= ,

[9-8-3]若简谐振动方程为x=0.10cos (20pi t+0.25pi ),式中x的单位mt的单位s,则t=2 s时的位移,速度和加速度为()A.