A mass weighing 4 lb stretches a spring 2 in. Suppose that the mass is given an additional 6 in displacement in the positive direction and then released. The mass is in a medium that exerts a viscous resistance of 6 lb when the mass has a velocity of 3 ft/s.
(a) Formulate the initial value problem that governs the motion of the mass.
(b) Solve the IVP to find the equation of motion.