Damped mass spring system oscillates at 205 Hz. The time constant of the system is 6.6s. At t=0 the amplitude of oscillation is 4.7 cm and the energy of the oscillating system is 26J. What is the amplitude of oscillation at t=9.9s? Answer in units of cm

Question

please help

Answer 1

y = .047 e^-(t/6.6)cos (410 pi t)

But all we need is e^ -(9.9/6.6)
= .223
and
.223*4.7 = 1.05 cm

Answer 2

thank you very much