A model rocket with a mass of 0.50 kg is fired vertically from the ground. Assume that it is streamlined enough that air resistance can be ignored. Suppose it ascends under the influence of a constant net force of 2.0 N acting in a vertical direction and travels for 6.0 s before its fuel is exhausted. Then it keeps moving as a particle-like object in free-fall as it continues upward, turns around, and falls back down. What is the net force on the rocket when it continues upward as a free fall particle? as it turns around? When it is traveling back toward the ground?