Question

A 75-m-long train begins uniform acceleration from rest. The front of the train has a speed of 18 m/swhen it passes a railway worker who is standing 125 m from where the front of the train started. What will be the speed of the last car as it passes the worker?

Answer 1

Answer:22.76 m/s

Explanation:

Given

Train length(L)=75 m

Front of train after travelling 125 m is 18 m/s

Time taken by the front of train to cover 125 m

$v^2-u^2=2as$

$18^2-0=2\times a\times 125$

$a=1.296 m/s^2$

Speed of the last part of train when it passes the worker i.e. front of train has to travel has to travel  a distance of 125+75=200 m

$v^2-u^2=2as$

$v^2=2\times 1.296\times 200$

$v=\sqrt{518.4}=22.76 m/s$