An ETS train moves at a speed of 140km/h while a KTM train moves at a speed of 140km/h. While going down the track, the speed of ETS train increases to 150km/h in 5 seconds and the speed of KTM train increases by 1/5 of the current speed of ETS train within the same time limit. Find the difference in acceleration, in km/h per second, between ETS train and KTM train.
