A box rests on top of a flat bed truck. The box has a mass of m = 16.0 kg. The coefficient of static friction between the box and truck is ?s = 0.81 and the coefficient of kinetic friction between the box and truck is ?k = 0.63. * The truck accelerates from rest to vf = 19.0 m/s in t = 12.0 s (which is slow enough that the box will not slide). What is the acceleration of the box? m/s2 * In the previous situation, what is the frictional force the truck exerts on the box?