CLEAR
Toprankers-Info

+91 7676564400

Mobile App

Get it on Google Play
Discussions
Select Date
Tags:

Articles

Discussions
Submit Discussion
ashwani kumar

· started a discussion

· 1 Months ago

Speed (Question: 109981.0 )

Why we assume speed of train 2nd greater than 1st

Question:
Two trains of equal length running at different speed take ‘a’ and ‘b’ second respectively to cross a pole. Then, time taken by the trains to cross each other when they are running in the same direction is :
Options:
A) \(\cfrac{2ab}{a+b}\)
B) \(\cfrac{2n}{a+b}\)
C) \(\cfrac{2ab}{a-b}\)
D) \(\cfrac{a-b}{2ab}\)
Solution:
Ans: (c) Let, length of both the trains = x metres

Then, Speed of the first train \(=\cfrac{x}{a}m/s\)

And, speed of the second train \(=\cfrac{x}{b}m/s\)

We further assume that speed of the second train is more than that of the first train

Total distance = x + x = 2x metres 

Relative speed \(=\cfrac{x}{b}-\cfrac{x}{a}=\cfrac{(a-b)x}{ab}m/s\)

\(\therefore\) Time taken by trains to pass each other 


Knowledge Expert

· commented

· 1 Months ago

Dear student Given answer is correct In the Question Given is the running same direction, that means speed is substract. and follow the Best wishes Team TR
-logo
We at aim to provide most comprehensive content & test for practice which is carefully divided into various chapters and topics to help you focus on your weak areas.Our Practice mock test gives you unmatched analytics to help you realize your strong areas,time management and improvement areas.Our Short & Crisp notes on each topic will help you to quickly revise the topic along with the tips & tricks of the exams.
More About
-Info
-Info

Mobile App

Get it on Google Play
About Us Campus Ambassador Careers Contact Us Refund Policy

All Rights Reserved Top Rankers

User Policy
Disclaimer
Terms & Conditions