Amass of 20 g stretches a spring 5 cm. suppose that the mass is also attached to a viscous damper with a damping constant of 400 dyn·s/cm. if the mass is pulled down an additional 2 cm and then released, find its position u at any time t. plot u versus t. determine the quasi frequency and the quasi period. determine the ratio of the quasi period to the period of the corresponding undamped motion. also find the time τ such that |u(t)| < 0.05 cm for all t > τ.