Question

a train of length 120m long travel at a speed of 54 km /hr , then what time will a train take to cross a tree? ​

Answer 1

Answer:

6480 is your proper answer

Answer 2

Given

Length of train =120m

Speed of train =54km/hr

To Find

Time taken by train to cross a tree ?

when we have to convert km/hr into m/s

$\sf\bold{\sf \longmapsto \dfrac{km}{hr} = \dfrac{1000 \times m}{3600 \times s}}$

$\sf\bold{\sf \longmapsto \dfrac{km}{h} = \dfrac{5}{18} \times \dfrac{m}{s}}$

$\sf \longmapsto \: 54kmhr = {\cancel{54 }3}\times \dfrac{5}{{\cancel{18}}} = 15m/s$

$\sf \boxed{ \bold{{Distance = Speed \times time}}}$

Length of train would be considered as distance

$\sf \longmapsto120 = 15 \times t$

$\sf \longmapsto \dfrac{120}{15} = t$

$\sf \longmapsto \: t = 8secs$

$\sf\therefore\:The\:train \:will\:take\:\bold{8\:seconds}$$\sf\:to\: cross\:a\:tree$