A train, weighing
136 tons,
was moving along a horizontal straight railway with a uniform velocity of
14.7 m/s.
While the train was moving, the last carriage, weighing
17 tons,
was separated and decelerated to completely stop after
80 seconds.
If the resistance per ton of the trainโs mass was constant,
determine how many seconds
it took for the distance between the train and the separated carriage to be
42 m.