A pencil making machine took 1⁄10 of a second to make enough pencils to fill 1⁄9 of a box. At this rate, how long would it take the machine to fill the entire box?

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).