Question

A train is moving with an initial velocity of 20m/s is brought to rest in 5 seconds. Calculate the retardation

Answer 1

u = 20m/s
v= 0
t= 5s
retardation = v-u/t
= -20/5= -4m/s^2

Answer 2

u=0
v =20
t=5
v=u-at
20=0-5a
a=-4
retardation =4 m/s^2