A train is moving at a speed of `100 m s^(-1)` comes to rest in 5 seconds. Find its retardation.

Explanation

Initial velocity of the train, `u = 100 m s^(-1)` final velocity of the train `v=0 m s^(-1)` ms time taken by the train to come to rest, t=5 s
`therefore` acceleration of the train
`a-(v-u)/(t)=(0-100)/(5)=-20 m s^(-2)` Hence, retardation of the train =20 m `s^(-2)`