Saved Bookmarks
| 1. |
A uniform wire (Y=2xx10^11 N//m^2)is subjected to a longitudinal tensile stress of 5xx10^(7) N//m^2. If the overall volume change in the wire is 0.02% the fractional decrease in its radius is 5kxx10^(-6)Find the value of k |
|
Answer» Solution :STRAIN=`(DELTAL)/l = "stress"/Y=(5xx10^7)/(2XX10^11)=2.5xx10^(-4)` Volume V=Al `DeltaV=Adeltal+l DeltaA` `(DeltaV)/V =(Deltal)/l =(DeltaA)/A` `rArr 2xx10^(-4)=2.5xx10^(-4)+(DeltaA)/A` `rArr (DeltaA)/A=0.5xx10^(-4)` `therefore (DeltaA)/A=(2Deltar)/r` `|(DELTAR)/r|=1/2|(DeltaA)/A|=1/2xx0.5xx10^(-4)=0.25xx10^(-4)` k=5 |
|