When a 260 g mass is hung from a vertical spring the new equilibrium position moves down by 8.35 millimeter. The position is measured positively downward from this new equilibrium (x=0). The mass is set into motion and the timer started (t=0) when the mass is moving through the equilibrium point downward at 9.60 m/s. Find the equation of position of time and the equation of velocity versus time.