011-40705070  or  
Call me
Download our Mobile App
Select Board & Class
  • Select Board
  • Select Class

If the diameter of the cross section of the wire is decreased by 5%,how much %will the length be increased so that the volume remains the same

Asked by Bharati S (parent) , on 14/10/09

Become Expert
Score more in Math
Start Now with Video Lessons, Sample Papers, Revision Notes & more for Class-X - CBSE 

BEST ANSWER Certified by MeritNation Expert  

 V = pi.h.r^2 (cylinder)

When diameter is decreased by 5%, radius also is decreased by 5%. So new radius is 19r/20.

So V becomes pi.h.(19r/20)^2 = pi.h.(361r^2)/400.

But you want to maintain the volume at a constant, so h is to be multiplied by 400/361 to keep it constant.

So length is to be incresed by 400/361 - 1 = 39/361 times, i.e. 39 x 100/361 = 10.8033 %

Posted by Suresh Anand (student) on 6/2/12

This conversation is already closed by Expert

More Answers

thankyou for your reply.....what are you studying?

Posted by Bharati S (parent) on 18/10/09

Ask a QuestionHave a doubt? Ask our expert and get quick answers.
Show me more questions