A steel rod of cross-sectional area1m^(2) is acted upon by forces shown in the fig. Determinethe totalelongation of the bar. Take Y=2.0xx10^(11)N//m^(2).

A steel rod of cross-sectional area1m^(2) is acted upon by forces show

1.	A steel rod of cross-sectional area1m^(2) is acted upon by forces shown in the fig. Determinethe totalelongation of the bar. Take Y=2.0xx10^(11)N//m^(2).
Answer» Solution :The ACTIONOF forces on eachpartof rod is shown in fig. We know that the extension DUE to external force F is given by `Delta_(AB)=(Fl)/(AY)` `Deltal_(AB)=((60XX10^(3))XX1.5)/(1xx2xx10^(11)) =4.5xx10^(-7)m` `Deltal_(BC)=((70xx10^(3))xx1)/( 1xx2xx10^(11)) =3.5xx10^(-7)m` and `Deltal_(CD)=((50xx10^(3))xx2)/(1xx2xx10^(11))=5.0xx10^(-7)m` The total extension `Delta=Delta_(AB)+Delta_(BC)+Delta_(CD)` `=4.5xx10^(-7)+3.5 xx 10^(-7)+5.0xx10^(-7)=13xx10^(-7)m`