Question

a train moving with a velocity of 20 m per second is brought to rest by applying brakes in 5 seconds calculate the retardation

Answer 1

Given that,
U = 20 m/sec
V = 0
T = 5 sec
A = v - u / t
= 0 - 20 / 5
= -20/5
= -4 m/s^2

Answer 2

Initial velocity =20m/s
Final velocity =0m/s
Time =5 seconds
Acceleration =v-u/t= 0-20/5=-20/5=-4