A mass weighting 16 pounds stretches a spring 8/3 feet. The mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force numerically equal to onehalf the instantaneous velocity. Find the equation of motion x(t) if the mass is driven by an external force equal to f(t)=10 cos3t. Find the time at which the mass attains its extreme displacement from the equilibrium position. What is the position of the mass at this instant?