Assuming that the distribution of times is mound shaped and approximately symmetric, approximately what
percentage of times are between 25 and 45 minutes?
Less than 20 minutes or greater than 50 minutes? Less
than 20 minutes?

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).