Physics - Elasticity Question with Solution | TestHub

Let$l_0$be the unstretched length and$l_3$be the length under a tension of 9 N. Then

$Y=\frac{4l_0}{A\left(l_1-l_0\right)}=\frac{5l_0}{A\left(l_2-l_0\right)}$

$=\frac{9l_0}{A\left(l_3-l_0\right)}$

These give$\frac{4}{l_1-l_0}=\frac{5}{l_2-l_0}\Rightarrow l_0=5l_1-4l_2$

Further,$\frac{4}{l_1-l_0}=\frac{9}{l_3-l_0}$

Substituting the value of$l_0$and solving, we get$l_3=5l_2-4l_1$