t=0.5s a=-wAcos(2×0.5) -4 r2×0.17=-0.419m/s f=ma=10×103×(-0.419) =-0.419×103N 0.12=0.24cos(2利 2元 2 →t= S 3 3 结束返回f =ma 2 a= ω A cos (π × 0.5) 2 = × 0.17 1 4π2 = 0.419m/s2 = 10×10- 3×(-0.419) = -0.419×10- 3 N t=0.5s 0.12 =0.24 cos( ) 2 πt = 1 cos( ) 2 πt 2 = 2 πt 3 2π t = 3 2 s 结束 返回