- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
A road has a diameter $0.7\ m$ and its width is $1.2\ m$. Find the least number of revolutions that the roller must take in order to level a playground of size $120\ m\times 44\ m$.
Given: A road has a diameter $0.7\ m$ and its width is $1.2\ m$. Size $120\ m\times 44\ m$.
To do: To find the least number of revolutions that the roller must take in order to level a playground.
Solution:
As given, Diameter of a road roller $=0.7\ m=70\ cm$
So, radius $( r)=\frac{70}{2}$
$=35\ cm=\frac{35}{100}$ m
And width $( h)=1.2\ m$
Now, curved surface area$=2\pi rh=2\times \frac{22}{7}\times \frac{35}{100}\times 1.2\ m^2$
$=\frac{264}{100}\ m^2$
Area of playground$=120\ m\times 44\ m=5280\ m^2$
Hence, the number of revolutions made by the road roller $=\frac{5280}{264}\times 100=2000$ revolutions.
Advertisements