Consider a 22 Ton railrod flatcar on which are located two automobiles facing one another and located at each end of the flatcar. Vehicle A weights 5,000lb and vehicle B weights 1,500. Assuming vehicle A starts from rest and accelerates at 0.2g for 2 sec and then continues at constant speed and car B accelerates at a(b) ft/s^2 for 2 sec and then continues at constant speed, calculate a(b) such that the flatcar does not move.