CLEAR
Toprankers-Info

+91 7676564400

Mobile App

Get it on Google Play
Discussions
Select Date
Tags:

Articles

Discussions
Submit Discussion
Jagdish Yadav

· started a discussion

· 1 Months ago

Ambiguity (Question: 107809.0 )

Relative speed should have been sum of both speeds. 18=30 plus speed 2 .
Do we take mod value in relative speed cases

Question:

The driver of an ambulance sees a school bus 40 meters ahead of him. After 20 seconds, the school bus is 60 meters behind. If the speed of the ambulance is 30 km/hr, then what is the speed of the school bus?

Options:
A) 10 km/hr.
B) 12 km/hr.   
C) 15 km/hr.   
D) 22 km/hr.
Solution:
Ans: (b) 

Relative Speed,
= \({}\left ( \cfrac {Total.distance}{Total.time} \right )\)
=\(\cfrac{60+40}{20}\)
= 5 m/s =\(\cfrac{5\times18}{5}\) = 18 kmph
Relative Speed = (speed of ambulance - speed of school bus)
Speed of school bus = speed of ambulance - relative speed.
= 30-18 = 12 kmph.

Knowledge Expert

· commented

· 1 Months ago

Dear Student,
Calculate the relative speed of the car with respect to the bus i.e considering the bus to be stationary, which comes to 5 meters per second , 5 m/s. (Distance = 100 m, time = 20 s)

Actual velocity of the car minus relative velocity of the car gives velocity of the bus which comes to 3.33 m/s or 12 kmph.
Keep Learning with Us
Best Wishes
Team Toprankers
-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