Question

A moving train is brought to rest within 20 s by applying brakes. Find the initial velocity, if the
retardation due to brakes is 4m/s2

Answer 1

Final velocity (v)=0m

Time(t)= 20 seconds

Acceleration=4m/s^2

Initial velocity=?

a=v-u/t

a=0-u/20

4×20=0-u

80=0-u

u=80-0

u=80m/s

Initial velocity is 80m/s