A mass of 0.5 kg stretches a spring 0.09 m. The mass is in a medium that exerts a viscous resistance of 38 N when the mass has a velocity of 4 ms. The viscous resistance is proportional to the speed of the object. Suppose the object is displaced an additional 0.08 m and released. Find an function to express the object's displacement from the spring's natural position, in m after t seconds. Let positive displacements indicate a stretched spring, and use 9.8 ms2 as the acceleration due to gravity. u(t) =