1. A mass attached to the end of a spring is stretched a distance x from equilibrium and released. At what distance from equilibrium will it have acceleration equal to half its maximum acceleration? My answer was 1/2A, but the correct answer was 1/2x, I don't know if there is a difference between these two. But I mean x may not be the amplitude, but I think the answer should be the half of its Amplitude. 2. A mass of 2.62 kg stretches a vertical spring 0.315 m. If the spring is stretched an additional 0.130 m and released, how long does it take to reach the (new) equilibrium position again? Here, what does it mean by new equilibrium position? 0.315m is the equilibrium point? Thanks for help.