Elongations in A and B are same ⇒ΔlA​=ΔlB​AA​⋅YA​TA​lA​​=AB​⋅YB​TB​lB​​⇒rA2​YA​TA​​=rB2​YB​TB​​⇒TB​TA​​=(rB​rA​​)2−(YB​YA​​)Given, rB​rA​​=32​ and YB​YA​​=23​∴TB​TA​​=(32​)2(23​)=32​For rotational equilibrium of bar; taking moments about point of suspension ' P ', TA​⋅x=TB​(l−x)⇒xl−x​=TB​TA​​=32​[ form E q .(i)]⇒x150−x​=32​150×3=5x[∴l=150 cm]orx=90 cm( from P)
