For Train 1,
u = 15 m/s ; a = -0.2 m/s2 ; v = 0
Distance travelled by train 1 before stopping (S1) = \(\frac{v^2 - u^2}{2a}\)
= \(\frac{-225}{-0.4} = 562.5 m\)
For Train 2,
u = 20 m/s ; a = -0.2 m/s2 ; v = 0
Distance travelled by train 2 before stopping (S2) = \(\frac{v^2 - u^2}{2a}\)
=\(\frac{-400}{-0.4} = 1000m\)
Therefore, final distance between the two trains = [(2000) - (1000 + 562.5)] = 437.5 meters