Question

if a train travelling at 72 km/h is to be brought to rest in a distance of 200 m then its retardation should be?

Answer 1

the retardation should be 1m/s^2
refer to the image

Answer 2

Answer:

$=> 1ms^{ - 2}$

Explanation:

$=> Speed \: of \: the \: train \: = 72 \: kmph \\ (72kmph = 72 \times 5 \div 18 = 20 \: ms^{ -1}$

$=> Distance \: travelled \: by \: train \: = 200 \: m$

$Now, \: by \: using \: eauation \: of \:motion : \\ => {v}^{2} - {u}^{2} = {2as}$

$v \: = 0 \\ u = 20 \: ms^{ - 1} \\ => 0 = 20 \times 20 \div 2 \times 200 \times a \\ => a = {1 \: m}^{ - 2}$

$Hope \: it \: helps \:$

$@charlie16$