1. The problem statement, all variables and given/known data A locomotive accelerates a 25-car train along a level track. Each car has a mass of 6.8e104 kg and is suject to a drag force f = 250v, where v is the speed in m/s and the force f is in N. At the instant when the speed of the train is 44 km/h, the acceleration is 0.20 m/s2. (a) What is the force exerted by the locomotive on the first car? (b) Suppose that the force found in part (a) is the greatest force the locomotive can exert of the train. What, then, is the steepest grade up which the locomotive can pull the train at 44 km/h? 2. Relevant equations f=ma 3. The attempt at a solution no attempt; no idea how to approach problem.