\(\text { Acceleration of the system }=\frac{\vec{F}_{\text {net }}}{m}\)
\(=\frac{32-20}{3}=4 \,m / s ^2\)
Free body diagram of \(20 \,cm\) part
Mass of \(20 \,cm\) part \(m^{\prime}=\frac{\text { Total mass }}{\text { Total length }} \times(20 \,cm )\)
\(=\frac{3}{30}(20)=2 \,kg\)
Using equation \(F_{\text {net }}=m^{\prime} a\)
\(32-T=2(4)\)
\(T=24\,N\)
$[g = 10\, {m} / {s}^{2} ]$