Chapter 4.10, Problem 14E

An $8\text{-kg}$ mass is attached to a spring hanging from the ceiling and allowed to come to rest. Assume that the spring constant is $40\text{N}/\text{m}$ and the damping constant is $3\text{N-}\text{sec}/\text{m}$. At time $t=0$, an external force of $2\sin \left(2t+\pi /4\right)\text{N}$ is applied to the system. Determine the amplitude and frequency of the steady-state solution.