Question

the train is moving with 144 km/h and suddenly comes at rest in 5 second, what will be its retardation?

Answer 1

u = 144 km/h

$= \: 144 \times \frac{5}{18} \: m {s}^{ - 1}$

$= \: 40m {s}^{ - 1}$

$v \: = 0 \: m {s}^{ - 1}$

t = 5s

$v = u + at$

$0 = 40 + 5a$

$=> a = - 8 \: m {s}^{ - 2}$

retardation is of 8m/s2

Answer 2

U=144km/h

=144*5/18

=40m/s

t=5s