If a train travelling at 36kmph is brought to rest in 400m what is the retardation?

Answer 1

v^2 - u^2 = 2 a s
now it is given
v = 0
u = 36kmh or 36*5/18 = 10 mps
a = ?
s = 400
=> -100 = 2 a 400
=> a = - 1/8

so retardation is 1/8 meter per secound square.