Physics
posted by Michael on .
A freight train has a mass of 1.2 × 107 kg. If the locomotive can exert a constant pull of 5.0 × 105 N, how long would it take to increase the speed of the train from rest to
89.2 km/h? (Disregard friction.) Answer in units of s.

The acceleration rate with that force acting is
a = F/m = 0.0417 m/s^2
89.2 km/h = 24.78 m/s is the speed you with to attain.
Solve this equation for the required time, t:
(1/2) a t^2 = 24.78 m/s