An 8kg block is suspended from a spring having stiffness A=80N/m. The block is given an upward velocity of 0.4 m/s when it is 90 mm above its equilibrium position. Assume that positive displacement is downward.
Determine the equation which describes the motion of the block measured from the equilibrium position. Express your answer in terms of the variable t. Enter the coefficients in meters to three significant figures.