Solve the problem by making up an equation. Jim can do all the work in an hour. Ben can do it in 40 minutes. How long will it take them to do all the work if they do it together?

Amass weighing 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 that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).