A train traveling with a speed of 36 km/h is brought to rest by applying brakes. If it travels a distance of 100 m under a uniform retardation before coming to rest, find the value of the retardation.

Initial velocity u = 36 km/h
                                 = 36 × m/s
                         = 10 m/s
Final velocity v = 0
Distance s = 100m
From the equations of motion, we have
v² – u² = 2as
a =
  =
  = = -0.5 m/s.