4.10.13 question a mass weighing 64 lb is attached to a spring hanging from the ceiling and comes to rest at its equilibrium position. at time t 0, an external force of f(t)= 3 cos 3t lb is applied to the system. if the spring constant is 15 lb/ft and the damping constant is 2 lb-sec/ft, find the steady-state solution for the system. use g 32 ft/sec the steady-state solution is y(t)-