Problem #7: When a 4 kg mass is attached to a spring whose constant is 100 N/m, it comes to rest in the equilibrium position. cos 2t is applied to the system. In the absence of damping, Starting at t=0, a force equal to f(t) 12e-5t (a) find the position of the mass when t=π. (b) what is the amplitude of vibrations after a very long time?