1. The problem statement, all variables and given/known data A freight train has a mass of 2.8 × 10^7 kg. If the locomotive can exert a constant pull of 8.1 × 10^5 N, how long would it take to increase the speed of the train from rest to 77.6 km/h? (Disregard friction.) Answer in units of s. 2. Relevant equations F=ma 3. The attempt at a solution I've tried everything, but I really have no clue on how to do this problem, if anyone can point me in the right direction or tell some formulas that would help it would be much appreciated.