A boy is pushing a moving box down a ramp angled 33.5º above the horizontal. The box has a mass of 35 kg and doesn't slide very easily against the ramp, having a coefficient of static friction of 0.71 and a coefficient of kinetic friction of 0.52. At the moment, the box is sliding down at 0.65 m/s and the boy is pushing down the ramp (parallel to the ramp) with 17 N.
a) What is the acceleration of the box? (Be sure to give a full answer.)
b) Assuming that the forces on the box have not changed, describe the box's motion 2.0 seconds later. Give as much detail as you can.