A mass of 1.5 kg stretches a spring 0.07 m\displaystyle {m}. The mass is in a medium that exerts a viscous resistance of 22 N\displaystyle {N} when the mass has a velocity of 2 ms\displaystyle \frac{{m}}{{s}}. The viscous resistance is proportional to the speed of the object.

Suppose the object is displaced an additional 0.03 m\displaystyle {m} and released.

Find an function to express the object's displacement from the spring's natural position, in m\displaystyle {m} after t\displaystyle {t} seconds. Let positive displacements indicate a stretched spring, and use 9.8 ms2\displaystyle \frac{{m}}{{s}^{{2}}} as the acceleration due to gravity.

u(t) =